{"title":"Explore Scientific Eyepieces","description":"\u003cp\u003eExplore Scientific Eyepieces — browse by series below. Part of \u003ca href=\"\/collections\/eyepieces\"\u003eEyepieces\u003c\/a\u003e.\u003c\/p\u003e","products":[{"product_id":"explore-scientific-82-deg-11mm","title":"Explore Scientific 82° Series 11mm Waterproof Eyepiece (1.25-Inch)","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 82° Series 11mm is a 1.25-inch barrel wide-field eyepiece with 15.6mm of eye relief and a 15.9mm field stop. Published dimensions are 87mm long and 48mm wide, at 9.8oz; 279g. The barrels are precision-machined metal with flat black internal surfaces to suppress stray light, the glass includes low dispersion types, and the coatings are enhanced multilayer deposition. The body is argon-purged for waterproofing.\u003c\/p\u003e\n\u003cp\u003e11mm is an upper-medium power in most telescopes: 90x in a 988mm refractor, 111x in a 1216mm apochromat, 136x in a 1500mm Maksutov, 68x in a 750mm Newtonian. That is the range where planetary detail, globular cluster resolution and the brighter planetary nebulae all sit.\u003c\/p\u003e\n\u003cp\u003eThe 82° apparent field is what separates this from a conventional eyepiece at the same focal length. At 90x the true field is 0.92° — nearly two Moon widths — where a 50° eyepiece at the same magnification would show roughly half that. On an undriven mount that difference is measured in how long a target stays in view before it needs re-centring.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven-mount users:\u003c\/strong\u003e 0.92° of true field at 90x is drift time, and drift time is what makes high-power observing on a manual mount pleasant rather than fiddly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary and lunar observers:\u003c\/strong\u003e 11mm lands in the useful magnification range of almost every aperture, and low dispersion glass with EMD coatings is aimed at the contrast that surface detail depends on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGlobular cluster and planetary nebula observers:\u003c\/strong\u003e this is the focal length where a globular begins to resolve into stars in a mid-sized telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who want an immersive view\u003c\/strong\u003e without moving up to a 2-inch eyepiece — at 9.8oz; 279g and 48mm wide it stays a 1.25-inch item.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extender users:\u003c\/strong\u003e Explore Scientific specifies compatibility with their 2X, 3X and 5X Focal Extenders.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e82° apparent field of view:\u003c\/strong\u003e the field fills enough of the visual field that the edge stops being an obvious frame.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e15.9mm field stop:\u003c\/strong\u003e the number that fixes the true field — 15.9 divided by telescope focal length, times 57.3.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e15.6mm eye relief:\u003c\/strong\u003e a workable figure at 11mm, where eye relief is normally the first thing a designer gives up.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ barrel:\u003c\/strong\u003e drops into any 1.25-inch focuser or diagonal, and into a 2-inch focuser with an adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision-machined metal barrels with flat black internal surfaces:\u003c\/strong\u003e internal blackening is what stops a bright object just outside the field from washing contrast out of the one inside it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow dispersion optical glass with enhanced multilayer deposition coatings:\u003c\/strong\u003e both aimed at transmission and colour fidelity across a wide field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged for waterproofing:\u003c\/strong\u003e an inert internal fill instead of ambient air, so internal fogging is designed out.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible with Explore Scientific 2X, 3X and 5X Focal Extenders,\u003c\/strong\u003e which turn 11mm into an effective 5.5mm, 3.67mm or 2.2mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished dimensions:\u003c\/strong\u003e 87mm long, 48mm wide, 9.8oz; 279g.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLunar and planetary observing at medium to high power.\u003c\/li\u003e\n\u003cli\u003eResolving globular clusters and picking out planetary nebulae.\u003c\/li\u003e\n\u003cli\u003eSplitting double stars where a wide field also keeps the surrounding pattern in view.\u003c\/li\u003e\n\u003cli\u003eComet nuclei and small galaxy groups.\u003c\/li\u003e\n\u003cli\u003eManual-mount observing at high power, where apparent field converts directly into time on target.\u003c\/li\u003e\n\u003cli\u003eSolar features with an appropriate front-mounted solar filter fitted to the telescope.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocuser:\u003c\/strong\u003e 1.25″ barrel, so it fits any 1.25-inch focuser or diagonal. In a 2-inch focuser it needs a 2-inch to 1.25-inch adapter, which we stock.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 11. A 750mm Newtonian gives 68x; a 1216mm apochromat 111x; a 2000mm SCT 182x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 15.9 ÷ focal length × 57.3. A 750mm Newtonian yields 1.21°; a 2000mm SCT 0.46°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 11 ÷ focal ratio. An f\/5 Newtonian gives 2.2mm, an f\/6.5 refractor 1.69mm, an f\/10 SCT 1.1mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e the 2X, 3X and 5X Explore Scientific extenders are specified as compatible. A 2X extender in a 1216mm telescope takes 111x to 222x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 9.8oz; 279g, light enough that balance is rarely affected on any but the smallest tube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e Explore Scientific does not publish a filter thread specification for this eyepiece, so that row is absent from the table below rather than estimated.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e15.6mm of eye relief is usable but not generous.\u003c\/strong\u003e Most observers get the full 82° field without difficulty; spectacle wearers who need to keep glasses on sometimes find the field edge cut off. If you observe with glasses, the longer eye relief in the 68° and 72° ED Series is the better match, and we stock both.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA wide apparent field asks more of the telescope at fast focal ratios.\u003c\/strong\u003e Below about f\/5 the outer field of any wide eyepiece shows more of the telescope's own coma, which is a property of the mirror rather than the eyepiece. A coma corrector addresses it, and we stock those.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e11mm is a medium-high power, so seeing governs the view.\u003c\/strong\u003e On a steady night it shows what the aperture can do; on a turbulent one a longer focal length shows more. That is atmosphere rather than optics.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count or a filter thread for this eyepiece,\u003c\/strong\u003e so those rows are absent below rather than estimated. If one of them decides the purchase, ask us and we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with the right adapter, but the design target is the eye.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops straight into any 1.25-inch focuser or diagonal and works immediately. There is nothing to assemble, collimate or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 11. A 1000mm telescope gives 91x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much sky does the 82° field actually show?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide the 15.9mm field stop by your telescope's focal length and multiply by 57.3. A 1000mm telescope gives 0.91°, close to two Moon widths at 91x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it work with a focal extender?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. Explore Scientific specifies the 2X, 3X and 5X Focal Extenders as compatible. A 2X gives the equivalent of a 5.5mm eyepiece while keeping the 82° apparent field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e15.6mm of eye relief works for many spectacle wearers, though seeing the entire 82° field with glasses is tight. If that is the deciding factor, the longer eye relief of the 68° and 72° ED Series is worth looking at, and we can compare them for you.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare to the 100° Series?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 100° is wider and physically much larger; the 82° at 11mm stays a 1.25-inch, 9.8oz eyepiece that any focuser will carry. Which suits you depends on your focuser size and how much weight your mount tolerates — tell us your setup and we will say which fits better.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: an 11mm, 1.25-inch, argon-purged eyepiece with an 82° apparent field, 15.6mm of eye relief and a 15.9mm field stop, at 9.8oz; 279g — medium-high power with enough field to keep a target in view on a manual mount, and specified to work with the 2X, 3X and 5X Focal Extenders. If you would like us to work out where it lands in your telescope alongside the eyepieces you already own, send us the focal length and your current set.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44012383076463,"sku":"EPWP8211-01","price":207.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/82_11_medium__67946.jpg?v=1766547978"},{"product_id":"explore-scientific-82-deg-14mm","title":"Explore Scientific 82° Series 14mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 82° Series 14mm is an argon-purged waterproof eyepiece on a 1.25-inch barrel, with a published 18.9mm field stop and 15.6mm of eye relief. At 83mm long, 48mm wide and 9.0 oz (256 g) it is unusually compact for an 82-degree design — most eyepieces of this apparent field at longer focal lengths need a 2-inch barrel and three times the weight.\u003c\/p\u003e\n\u003cp\u003e14mm is the medium-power focal length in most telescopes: 71x in a 1000mm instrument, 86x in a 1200mm SCT, 34x in a 480mm refractor. Paired with an 82° apparent field, that combination gives a true field of 1.08° at 1000mm — the 18.9mm field stop divided by focal length, times 57.3 — which is roughly two lunar diameters across at 71x.\u003c\/p\u003e\n\u003cp\u003eThe optical design uses low-dispersion glass and high refractive index elements under enhanced multilayer coatings. Internal barrel surfaces are flat black and the lens edges are blackened, both aimed at keeping stray light out of a wide field where there is more of it to control.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who want a wide field in a 1.25-inch focuser:\u003c\/strong\u003e at 256 g and 83mm long, this delivers 82 degrees without needing a 2-inch focuser or a rebalance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven mount users:\u003c\/strong\u003e an 82° field at medium power buys real drift time before the object leaves the view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers\u003c\/strong\u003e working on globular clusters, brighter galaxies and planetary nebulae, where 14mm sits at a useful compromise between image scale and field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTravellers and portable-setup owners:\u003c\/strong\u003e 9.0 oz in a small case adds an 82° field to a lightweight kit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers in dew-heavy conditions:\u003c\/strong\u003e the argon-purged, sealed body is built for damp nights.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e82° apparent field of view\u003c\/strong\u003e in a 1.25-inch barrel — the wide-field format without the 2-inch focuser requirement.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e18.9mm field stop:\u003c\/strong\u003e the published figure that determines your true field. Divide by telescope focal length and multiply by 57.3 for degrees.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e15.6mm eye relief,\u003c\/strong\u003e which at 14mm leaves room to observe without pressing your eye against the lens.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow-dispersion glass and high refractive index elements\u003c\/strong\u003e under enhanced multilayer coatings, aimed at contrast, resolution and a flat field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlat black internal barrel surfaces and blackened lens edges,\u003c\/strong\u003e which is how scatter is controlled in a design with a lot of glass and a wide field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon purged and waterproof:\u003c\/strong\u003e dry inert gas inside a sealed housing, so internal fogging is not part of a long session.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact and light:\u003c\/strong\u003e 83mm long, 48mm wide, 9.0 oz (256 g).\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMedium-power deep-sky observing — globular clusters, galaxies, planetary nebulae.\u003c\/li\u003e\n\u003cli\u003eLunar observing, where 82 degrees puts the whole disc in a wide frame at moderate power.\u003c\/li\u003e\n\u003cli\u003eOpen clusters that need both resolution and surrounding field.\u003c\/li\u003e\n\u003cli\u003eObserving on an undriven mount, where apparent field converts directly into time on target.\u003c\/li\u003e\n\u003cli\u003ePortable and travel setups built around a 1.25-inch focuser.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal\u003c\/strong\u003e directly, and a 2-inch focuser with a 2-inch to 1.25-inch adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length divided by 14. A 1400mm Maksutov gives 100x; a 750mm Newtonian gives 54x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 18.9 divided by focal length, times 57.3. A 1200mm SCT gives 0.90°; a 480mm refractor gives 2.26°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 14 divided by focal ratio — 2.3mm at f\/6, 1.4mm at f\/10. Comfortable figures in both cases.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e standard 1.25-inch threaded filters thread into the barrel. Narrowband and oxygen-III filters pair well with this focal length on nebulae.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the series:\u003c\/strong\u003e the 82° Series is parfocal, so a matched set holds the same focus position and eye placement as you change powers.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAn 82° field asks something of the observer.\u003c\/strong\u003e Taking in the whole view means moving your eye slightly rather than staring straight ahead, which is normal for wide-field designs and takes a session or two to become second nature.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count for this eyepiece,\u003c\/strong\u003e so that row reads as unpublished below rather than being estimated. If it is a figure you want before ordering, ask and we will put it to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEye placement is more particular than in a narrow-field eyepiece.\u003c\/strong\u003e 15.6mm of eye relief gives room to work with, and the fold-down eyecup sets a repeatable distance once you find it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA 1.25-inch barrel caps the true field.\u003c\/strong\u003e At 14mm and an 18.9mm field stop that cap is not in play — but if a still wider true field is what you are after, that means a longer focal length in a 2-inch format, and we stock those.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Projection imaging is possible with an adapter, though the design target here is the eye.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 1.25-inch focuser or diagonal and is ready to observe with. At 256 g it changes nothing about your telescope's balance, so there is nothing to adjust afterwards either.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 14. A 1000mm telescope gives 71x, a 1400mm gives 100x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow wide is the actual view?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 18.9mm field stop divided by your focal length, times 57.3. In a 1200mm SCT that is 0.90 degrees, which is a little under two lunar diameters.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy choose 82 degrees over a narrower field?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eTwo reasons: an object stays in view longer on an undriven mount, and there is enough surrounding sky that a cluster or a nebula sits in context rather than filling the frame edge to edge.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it need a 2-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. The barrel is 1.25 inches, which is what makes this a wide-field eyepiece you can use in a small refractor or a travel setup.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e15.6mm of eye relief is workable for many prescriptions and tight for some. Where taking glasses off is not an option, the long-eye-relief designs in the Explore Scientific range carry considerably more — tell us your situation and we will compare the figures for you.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 14mm argon-purged waterproof eyepiece with an 82° apparent field, an 18.9mm field stop and 15.6mm of eye relief, all in a 256 g body on a 1.25-inch barrel — a wide field at medium power that any telescope with a standard focuser can take. If you would like help deciding how it fits alongside eyepieces you already own, send us the list and your telescope's focal length and we will work out the gaps.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44012383109231,"sku":"EPWP8214-01","price":207.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/82_14_medium__19486.jpg?v=1766547984"},{"product_id":"explore-scientific-82-deg-18mm","title":"Explore Scientific 82° Series 18mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 82° Series 18mm is an argon-purged waterproof eyepiece with a 2-inch barrel, a published field stop of 25.3mm and 13mm of eye relief. The body measures 89mm long by 56mm wide and weighs 13.7 oz (390 g).\u003c\/p\u003e\n\u003cp\u003e18mm with an 82-degree apparent field is a medium-power eyepiece that still delivers a genuinely wide true field. The 25.3mm field stop is the figure that governs it: divide 25.3 by your telescope's focal length and multiply by 57.3 for the true field in degrees. In a 714mm refractor that is 2.03° at 40x; in a 1200mm Schmidt-Cassegrain, 1.21° at 67x.\u003c\/p\u003e\n\u003cp\u003eExplore Scientific builds the series around low-dispersion glass and enhanced multilayer coatings, in a precision-machined metal housing with flat-black internal surfaces to keep scattered light out of the field.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers:\u003c\/strong\u003e two degrees of true field in a medium-focal-length telescope frames the Veil, the Rosette and the larger open clusters whole while still magnifying enough to darken the background sky.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian owners:\u003c\/strong\u003e 82 degrees of apparent field is a long drift time at 40x to 70x on an undriven mount, which is where the extra field pays for itself.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who value a flat field:\u003c\/strong\u003e the low-dispersion glass and coating package are aimed at holding contrast and star shape out toward the field stop.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDamp-climate observers:\u003c\/strong\u003e the argon-purged, sealed housing is built for dew-heavy nights.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who use focal extenders:\u003c\/strong\u003e Explore Scientific specifically notes compatibility with extenders, so an 18mm can double as a 9mm equivalent behind a 2x.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e82° apparent field of view:\u003c\/strong\u003e a wide, immersive field where the edge of view sits outside the eye's central attention rather than framing it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e25.3mm field stop:\u003c\/strong\u003e the published figure that fixes true field exactly, rather than approximating it from apparent field and magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow-dispersion glass with enhanced multilayer coatings,\u003c\/strong\u003e the combination Explore Scientific specifies for contrast and flatness across the series.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged and sealed:\u003c\/strong\u003e an inert internal atmosphere that carries no moisture to condense on internal surfaces as the eyepiece cools.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e13mm eye relief\u003c\/strong\u003e published for this focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2-inch barrel\u003c\/strong\u003e taking standard 2-inch threaded filters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision-machined metal construction\u003c\/strong\u003e with flat-black internal surfaces to suppress scatter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished dimensions:\u003c\/strong\u003e 89mm long, 56mm wide, 13.7 oz (390 g).\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eWide-field deep-sky observing of nebulae, large open clusters and star fields.\u003c\/li\u003e\n\u003cli\u003eMedium-power views of globular clusters, where 40x to 70x starts to resolve the outer stars.\u003c\/li\u003e\n\u003cli\u003eLunar observing at moderate magnification with the whole disc comfortably framed in most telescopes.\u003c\/li\u003e\n\u003cli\u003eSweeping the Milky Way on an undriven mount, where the 82° field keeps targets in view.\u003c\/li\u003e\n\u003cli\u003eUse behind a focal extender as a medium-high-power eyepiece with the same wide apparent field.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRequires a 2-inch focuser or diagonal.\u003c\/strong\u003e The 2-inch barrel does not step down to 1.25 inches, so a telescope with only a 1.25-inch focuser is outside its range — the 82° Series does include 1.25-inch focal lengths, and we can point you to those.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 18. A 500mm Newtonian gives 28x, a 714mm refractor 40x, a 1200mm SCT 67x, a 1500mm Maksutov 83x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 25.3 ÷ focal length × 57.3. That is 2.90° at 500mm, 2.03° at 714mm, 1.21° at 1200mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e standard 2-inch threaded filters screw into the barrel. Broadband and narrowband nebula filters are the natural pairing at this focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e behind a 2x extender the 18mm behaves as a 9mm while keeping the 82° apparent field, which is a compact way to cover two powers with one eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e at 390 g it is a moderate load for a Dobsonian or a small refractor. Counterweights and magnetic balance weights handle any tip, and we stock them.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a 2-inch eyepiece.\u003c\/strong\u003e A 2-inch focuser or 2-inch diagonal is what it fits. If your telescope has a 1.25-inch focuser, the shorter focal lengths in the 82° Series come in 1.25-inch barrels and cover similar ground — tell us your telescope and we will point you at the right one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e13mm of eye relief is moderate.\u003c\/strong\u003e Comfortable for most observers with the eyecup adjusted; for observing with glasses on, the 72° ED Series is specified for longer eye relief and we stock it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAn 82° field asks the eye to move.\u003c\/strong\u003e Taking in the whole field means glancing around it rather than seeing all of it at once, which is normal for wide-angle designs and is part of what makes them absorbing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAt 390 g it can shift the balance\u003c\/strong\u003e of a lightly loaded Dobsonian or a short refractor. A small counterweight settles it, and it is not a heavy eyepiece by 2-inch standards.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count or a box-contents list\u003c\/strong\u003e for this eyepiece, so those rows are absent rather than estimated. We can ask our rep if either matters to you.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 2-inch focuser or diagonal and is ready to use immediately. There is nothing to assemble or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat true field will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide 25.3 by your telescope's focal length in millimetres and multiply by 57.3. A 1000mm telescope gives 1.45°; a 714mm refractor gives 2.03°.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit a 1.25-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — the barrel is 2 inches. A telescope with a 1.25-inch focuser is better served by one of the 1.25-inch focal lengths in the same series.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use filters with it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. Standard 2-inch threaded filters thread into the base of the barrel, which suits nebula filters particularly well at this field size.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with the 100° Series?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 100° designs give a wider apparent field in a larger, heavier body. The 82° 18mm at 390 g is the more manageable of the two on a light mount, and its 25.3mm field stop still delivers a genuinely wide true field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes the argon purging make a practical difference?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eOn cold, damp nights, yes. Sealed ordinary air carries moisture that condenses on internal surfaces as the eyepiece cools; argon does not.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: an 18mm 82° eyepiece with a 25.3mm field stop, 13mm of eye relief and a sealed argon-purged 2-inch body at 390 g — a medium-power eyepiece that still frames two degrees of sky in a short-focus telescope. If you would like to know exactly what true field it will give in the telescope you own, send us the focal length and we will work it out for you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44012383141999,"sku":"EPWP8218-01","price":262.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/82_18_medium__86634.jpg?v=1766547990"},{"product_id":"explore-scientific-82-deg-24mm","title":"Explore Scientific 82° Series 24mm Argon-Purged Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 82° Series 24mm is a 2-inch, argon-purged waterproof eyepiece with an 82-degree apparent field, 17.5mm of eye relief and a 33.5mm field stop. Explore Scientific gives its physical dimensions as 110mm long by 70mm wide, weighing 24.8 oz (704 g). It is item EPWP8224-01.\u003c\/p\u003e\n\u003cp\u003eThe field stop is the figure that defines what this eyepiece does. At 33.5mm, the true field of view is 33.5 divided by the telescope's focal length, converted to degrees — which works out to 1.92° in a 1000mm telescope, 1.94° in a 988mm f\/6.5 refractor, and 0.79° in a 2400mm Schmidt-Cassegrain. In a metre-class refractor that is nearly four full-Moon diameters of sky at 42x, held in an 82-degree apparent field that fills your peripheral vision rather than framing the view in a small porthole.\u003c\/p\u003e\n\u003cp\u003eTwenty-four millimetres is the upper-medium magnification step: 42x in a 1000mm telescope, 32x in a 750mm Newtonian, 79x in a 1900mm Maksutov. The exit pupil is 24 divided by the telescope's focal ratio — 3.7mm at f\/6.5, 2.4mm at f\/10 — which keeps the sky background dark while surface brightness on extended objects stays high.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky sweepers:\u003c\/strong\u003e almost two degrees of true field in a metre-focal-length telescope covers large open clusters, the sword of Orion and the Veil in single views.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian owners:\u003c\/strong\u003e 82 degrees of apparent field at 24mm buys a long drift time, so the object crosses a wide view slowly instead of shooting through a narrow one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComet observers:\u003c\/strong\u003e a bright comet with an extended tail wants exactly this combination of true field and moderate magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who wear glasses:\u003c\/strong\u003e 17.5mm of eye relief is generous, and it is enough that a spectacle lens can sit between eye and eyepiece with the field still fully visible.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone observing in dew:\u003c\/strong\u003e the argon-purged, sealed housing is built for damp air rather than merely tolerant of it.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e24mm focal length in a 2-inch barrel:\u003c\/strong\u003e 42x in a 1000mm telescope, with the barrel size that allows a large field stop.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e82° apparent field of view:\u003c\/strong\u003e wide enough that the field edge sits outside the eye's comfortable scanning range, which is what produces the sense of looking through an open window.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e33.5mm field stop:\u003c\/strong\u003e the physical aperture that sets the true field — 1.92° in a 1000mm telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e17.5mm eye relief:\u003c\/strong\u003e unusually generous for an ultra-wide design, and the reason this focal length works with glasses on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged and waterproof:\u003c\/strong\u003e the internal air is replaced with dry argon, which has no moisture in it to condense on internal surfaces as the temperature drops.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEnhanced multi-layer coatings:\u003c\/strong\u003e applied to raise transmission and hold contrast on low-surface-brightness targets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e110mm long, 70mm wide, 24.8 oz (704 g):\u003c\/strong\u003e a substantial ocular, sized as ultra-wide 2-inch designs generally are.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extender compatible:\u003c\/strong\u003e Explore Scientific specify this eyepiece as working with their focal extenders for a higher-power step.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLow and medium-power deep-sky observing — open clusters, large emission nebulae, the brighter galaxies.\u003c\/li\u003e\n\u003cli\u003eSweeping the Milky Way from a dark site, where true field is the governing quantity.\u003c\/li\u003e\n\u003cli\u003eComet observing, where the object and its tail need room in the frame.\u003c\/li\u003e\n\u003cli\u003eFraming the full lunar disc with dark sky around it at 42x in a metre-class telescope.\u003c\/li\u003e\n\u003cli\u003eUndriven and Dobsonian observing, where a wide apparent field lengthens the interval between nudges.\u003c\/li\u003e\n\u003cli\u003eServing as the finder eyepiece before switching to higher power on a located target.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e2-inch focusers and diagonals only.\u003c\/strong\u003e The 33.5mm field stop is larger than a 1.25-inch barrel can pass, so this eyepiece is 2-inch by necessity rather than by preference. Telescopes with 1.25-inch focusers cannot take it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 33.5 divided by your telescope's focal length in millimetres, multiplied by 57.3, gives the answer in degrees. A 1200mm SCT yields 1.60°; a 1900mm Maksutov yields 1.01°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length divided by 24. A 650mm refractor gives 27x, a 1500mm gives 63x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e Explore Scientific list their focal extenders as compatible. A 2-inch 3x extender turns this into an effective 8mm, taking a 1000mm telescope from 42x to 125x while the eye relief and eye position stay as they were.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e the 2-inch barrel accepts standard 2-inch threaded filters — an ultra-wide field and a broadband nebula filter are a natural pairing from a suburban site.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e at 24.8 oz this eyepiece shifts the balance point of a Dobsonian or a small refractor noticeably. Magnetic balance weights or a stiffer altitude bearing take care of it, and we stock the weights.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt weighs 24.8 oz and needs a 2-inch focuser.\u003c\/strong\u003e On a small refractor or a Dobsonian, swapping it in will change the balance. A counterweight on the tube or the rings settles it, and we can supply one sized to your telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 33.5mm field stop is close to the physical limit of a 2-inch barrel.\u003c\/strong\u003e That is a strength — you are getting close to the widest true field a 2-inch focuser can deliver at this magnification — and it is also the reason there is no 1.25-inch version of this eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFast telescopes ask more of a wide field.\u003c\/strong\u003e An 82-degree field in an f\/4 or f\/4.5 instrument shows the outer field more critically than in an f\/8, which is a property of every wide-field eyepiece rather than this one in particular. A coma corrector addresses the telescope's own contribution, and we stock them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish the element count for this model,\u003c\/strong\u003e so that row is absent rather than estimated. If it matters to your comparison, we can ask our Explore Scientific rep for the figure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon purging is about condensation, not depth rating.\u003c\/strong\u003e Its practical value is that a cold night does not fog the inside of the eyepiece, and dew on the outer surface wipes away.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. It slides into a 2-inch focuser or diagonal and is ready. The only practical consideration is rebalancing the telescope after fitting an eyepiece of this weight, which is a matter of moving a counterweight or sliding the tube in its rings.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much sky will I actually see?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 33.5mm field stop gives 1.92° of true field in a 1000mm telescope — close to four full-Moon diameters — at 42x. In a 2000mm SCT the same eyepiece gives 0.96° at 83x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it in a 1.25-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. The field stop is wider than a 1.25-inch barrel can accommodate, which is why this eyepiece is made in the 2-inch format only. For a 1.25-inch focuser, the shorter focal lengths in the 82° Series are the ones to look at.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes the eye relief really work with glasses?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e17.5mm is generous by ultra-wide standards, and it is in the range where most spectacle wearers can take in the full 82-degree field with their glasses on. The fold-down eyecup is what sets the right distance.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does argon purging do?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe manufacturer replaces the air sealed inside the eyepiece with dry argon. Argon carries no water vapour, so there is nothing inside to condense on the internal glass when the eyepiece cools below the dew point.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it work with a focal extender?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes — Explore Scientific specify their focal extenders as compatible. A 3x extender in the 2-inch format makes it behave as an 8mm while keeping the same comfortable eye position.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 24mm ultra-wide eyepiece with an 82-degree apparent field, a 33.5mm field stop, 17.5mm of eye relief and an argon-sealed 2-inch body — close to the widest true field a 2-inch focuser can give at upper-medium power. If you would like to know exactly how much sky it will show in the telescope you own, send us the focal length and we will work the figure out with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44012383338607,"sku":"EPWP8224-01","price":346.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/82_24_medium__23542.jpg?v=1766547995"},{"product_id":"explore-scientific-82-deg-30mm","title":"Explore Scientific 82° Series 30mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 82° Series 30mm is the low-power, wide-field end of the 82° range, built on a 2-inch barrel with an argon-purged waterproof housing. It carries a published 43mm field stop, 22mm of eye relief and an 82° apparent field, and measures 131mm long by 82mm wide at 35.5oz (1007g). It is a substantial piece of glass, and the size is a direct consequence of what it does.\u003c\/p\u003e\n\u003cp\u003e43mm is essentially the largest field stop a 2-inch barrel can pass, which means this eyepiece delivers about as much true field as the 2-inch format physically allows. In a 952mm refractor that works out to 2.6°; in a 1200mm Schmidt-Cassegrain, 2.05°; in a 1500mm Maksutov, 1.64°. Magnification is modest by design — 32x in that 952mm refractor — and the point is the amount of sky in view, not the size of what is in it.\u003c\/p\u003e\n\u003cp\u003eExplore Scientific specifies precision-machined metal barrels, low-dispersion optical glass, enhanced multi-layer deposition coatings and flat black internal surfaces to suppress scatter. The 22mm of eye relief is generous for any eyepiece and unusual in one with this much apparent field.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRich-field observers:\u003c\/strong\u003e a 43mm field stop is the widest true field a 2-inch eyepiece can give, which is what makes large open clusters, the Veil, the Andromeda halo and the great nebulae fit as objects rather than fragments.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian owners:\u003c\/strong\u003e low power plus 82° of apparent field means an object crosses the view slowly, and the combination is about as forgiving as manual tracking gets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 22mm of eye relief is enough to take in a large part of an 82° field with glasses on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDamp-climate observers:\u003c\/strong\u003e the argon-purged sealed body is built for dew-heavy sites and cold, humid nights.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e82° apparent field of view:\u003c\/strong\u003e the immersive end of the range, where the field edge sits outside your comfortable direct vision and the view feels like a window rather than a tube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e43mm field stop:\u003c\/strong\u003e published, and about the physical limit of what a 2-inch barrel can pass. This is the number that sets the true field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e22mm eye relief:\u003c\/strong\u003e generous, and unusually so for a wide-field eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2″ barrel:\u003c\/strong\u003e required to carry a field stop this large, and standard on any 2-inch focuser or diagonal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow-dispersion optical glass\u003c\/strong\u003e in the design, aimed at colour fidelity across a very wide field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEnhanced multi-layer deposition (EMD) coatings:\u003c\/strong\u003e raise transmission and hold contrast, which matters most on the faint extended objects this focal length is built to frame.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlat black internal surfaces\u003c\/strong\u003e to minimise light scatter inside the barrel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged, sealed waterproof construction:\u003c\/strong\u003e inert gas in place of moist air, so internal fogging is not a failure mode.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eWide-field deep-sky sweeping — the Milky Way, large open clusters, extended nebulae and star fields.\u003c\/li\u003e\n\u003cli\u003eFraming large objects that overflow a narrower field: the Veil, the North America Nebula, the Pleiades, M31 with its companions.\u003c\/li\u003e\n\u003cli\u003eLow-power finding and identification before switching to a high-power eyepiece.\u003c\/li\u003e\n\u003cli\u003eManual Dobsonian observing, where low power and a wide apparent field together minimise nudging.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e2-inch focuser or diagonal required.\u003c\/strong\u003e The 43mm field stop is what makes the 2-inch format necessary — a 1.25-inch barrel physically cannot pass this much field. If your telescope has a 1.25-inch focuser only, we can advise on whether a 2-inch upgrade is available for it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 30. A 750mm Newtonian gives 25x; a 952mm refractor 32x; a 1200mm SCT 40x; a 2000mm SCT 67x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 43mm ÷ telescope focal length × 57.3. A 750mm scope gives 3.3°; a 1200mm gives 2.05°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 30mm divided by your telescope's focal ratio. At f\/5 that is 6mm, at f\/10 it is 3mm. In telescopes slower than about f\/6 the exit pupil stays within what a dark-adapted eye can use comfortably; in very fast instruments some of the light cone can fall outside the pupil at this focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e takes 2-inch threaded filters, which screw into the bottom of the barrel. A UHC or O-III filter in front of a 30mm at 82° is one of the great combinations in visual deep-sky observing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e Explore Scientific designs its focal extenders to work with this series, raising magnification while preserving the native field and eye relief characteristics of the eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e at 35.5oz this eyepiece shifts the balance of a small refractor or a Dobsonian noticeably. Counterweights and adjustable tube rings solve it, and we can suggest what suits your telescope.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt weighs 35.5oz (1007g).\u003c\/strong\u003e That is enough to swing a Dobsonian out of balance or to tip a light refractor on an undersized mount. Counterweights and rebalancing solve it, and we stock the parts — tell us your telescope and we will suggest the simplest fix.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt needs a 2-inch focuser or diagonal.\u003c\/strong\u003e There is no adapter route from a 43mm field stop into a 1.25-inch barrel, since the barrel itself is the limit. Many telescopes can be upgraded to a 2-inch focuser, and we can tell you whether yours is one of them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow power is the point.\u003c\/strong\u003e At 30mm this eyepiece frames wide fields; planetary detail and close double stars call for a much shorter focal length, and the 82° Series covers those too.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count or the box contents\u003c\/strong\u003e for this eyepiece, so those rows read as unpublished below. If either is important to you, ask and we will check with our Explore Scientific rep.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 2-inch focuser or diagonal and is ready to use, with nothing to assemble or adjust. The one practical consideration is its weight: at 35.5oz it is worth rebalancing the telescope after inserting it, particularly on a Dobsonian or a small refractor.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it in a 1.25-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — the 43mm field stop needs the full 2-inch barrel. If your telescope is 1.25-inch only, send us the model and we will let you know whether a 2-inch focuser upgrade exists for it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow wide is the actual view?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide the 43mm field stop by your telescope's focal length and multiply by 57.3. A 1000mm telescope gives 2.46°, or about five full-Moon widths.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e22mm of eye relief is generous and makes that workable. With an 82° field, the outermost edge is easier to reach with glasses off, but most of the field is available either way.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it work with a focal extender?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. Explore Scientific designs its focal extenders to work with this series, increasing magnification while keeping the eyepiece's native field and eye relief behaviour intact.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 30mm eyepiece with an 82° apparent field, a 43mm field stop at the practical limit of the 2-inch format, 22mm of eye relief and an argon-purged waterproof body — the widest true field a 2-inch eyepiece can deliver, in a 35.5oz package that earns the space it takes. If you would like a hand working out whether your telescope's focuser and balance will take it comfortably, send us the model and we will go through it with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44012383371375,"sku":"EPWP8230-01","price":415.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/82_30_medium__21584.jpg?v=1766548001"},{"product_id":"5-5mm-100-series-argon-purged-waterproof-eyepiece","title":"Explore Scientific 100° Series 5.5mm Argon-Purged Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 100° Series 5.5mm is the short focal length end of the widest apparent field Explore Scientific builds. It uses a 2.00″ barrel, measures 150mm long and 56mm wide, and weighs 21.6oz (612g) — a large, dense eyepiece, which is what a 100° field at 5.5mm requires physically.\u003c\/p\u003e\n\u003cp\u003eAt 5.5mm this is high magnification in almost any telescope: 150x in an 826mm refractor, 218x in a 1200mm Dobsonian, 364x in a 2000mm SCT. The published field stop is 9.6mm, which puts the true field at roughly 0.46° at 1200mm — slightly less than a full Moon — and eye relief is 10.5mm.\u003c\/p\u003e\n\u003cp\u003eThe housing is argon-purged and internally sealed, tested by submersion to 1 metre for 30 minutes, and the optics are multi-coated for maximum contrast. Registering the eyepiece with Explore Scientific within 60 days activates their lifetime coverage.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who want the spacewalk view at high power:\u003c\/strong\u003e at 100° the field edge is well outside where the eye naturally looks, so the framing effectively disappears.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven-mount users at high magnification:\u003c\/strong\u003e apparent field is what buys drift time, and 100° buys close to twice what a 52° eyepiece does at the same power.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary and lunar observers\u003c\/strong\u003e with a telescope and a site that support 200x and beyond.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGlobular cluster and planetary nebula observers,\u003c\/strong\u003e where high magnification and a dark background sky pull faint structure out.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers in dew-prone conditions,\u003c\/strong\u003e given the sealed, argon-filled body.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e100° apparent field of view:\u003c\/strong\u003e the widest series Explore Scientific produces, where the eye scans within the field rather than taking it in at once.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e9.6mm field stop:\u003c\/strong\u003e the figure that sets true field — 57.3 × 9.6 ÷ your telescope's focal length gives the field in degrees.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e10.5mm eye relief:\u003c\/strong\u003e workable at 5.5mm, a focal length where eye relief is the usual sacrifice.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2.00″ barrel:\u003c\/strong\u003e the large barrel is what carries a 100° field at a short focal length; a 1.25-inch barrel could not pass the same light cone.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged and internally sealed:\u003c\/strong\u003e tested by submersion to 1 metre of water for 30 minutes, with an inert fill that gives internal fogging nothing to condense from.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMulti-coated optics\u003c\/strong\u003e for contrast on low-surface-brightness detail at high magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished dimensions:\u003c\/strong\u003e 150mm long, 56mm wide, 21.6oz (612g).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific lifetime coverage\u003c\/strong\u003e on registration within 60 days of purchase.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHigh-power lunar observing, where a wide field keeps a whole region of the terminator in view.\u003c\/li\u003e\n\u003cli\u003ePlanetary detail on nights of steady seeing.\u003c\/li\u003e\n\u003cli\u003eGlobular clusters, planetary nebulae and compact galaxies at high magnification.\u003c\/li\u003e\n\u003cli\u003eDouble-star work at 150x and above.\u003c\/li\u003e\n\u003cli\u003eManual-mount high-power observing, where apparent field converts directly into observing time.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRequires a 2-inch focuser or diagonal.\u003c\/strong\u003e The 2.00″ barrel does not step down, so a 1.25-inch-only focuser is outside its range. We can check your focuser against it before you order.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 5.5. An 826mm refractor gives 150x; a 1200mm Newtonian gives 218x; a 1500mm Maksutov gives 273x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 57.3 × 9.6 ÷ focal length — about 0.46° at 1200mm and 0.67° at 826mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 5.5 divided by focal ratio — 1.17mm at f\/4.7 and 0.55mm at f\/10.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e 21.6oz at the focuser end is a genuine load. On a Dobsonian, tube friction or a counterweight handles it; on a small refractor, moving the tube back in its rings does the same job.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e 2-inch threaded filters are the match. Neutral density and variable polarising filters are the usual companions for lunar work at this magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e 5.5mm is already short, and an extender on top of it exceeds what most apertures and most nights will support. A longer eyepiece in the series is the better base for one.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a large, heavy 2-inch eyepiece.\u003c\/strong\u003e 150mm long and 612g means both a 2-inch focuser and a moment's thought about balance. Both are easily handled, and we can suggest a counterweight if your telescope needs one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeeing sets the ceiling at 5.5mm.\u003c\/strong\u003e Around 218x in a 1200mm telescope, this is a good-night eyepiece — steady air rewards it and turbulent air will not. A longer focal length alongside it covers the rest of the nights.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e10.5mm of eye relief is workable rather than generous.\u003c\/strong\u003e If you observe with glasses on, the 82° Series LER designs carry more eye relief, and we stock those.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe exit pupil is small.\u003c\/strong\u003e At f\/10 it is 0.55mm, which can make floaters in your own eye visible. That is a normal effect of high magnification rather than anything happening in the optics.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count, a group count or a filter thread specification\u003c\/strong\u003e for this eyepiece, so those rows are absent below rather than estimated. If one of those decides it for you, ask and we will take the question to our Explore Scientific contact.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 2-inch focuser or diagonal and is ready to use straight away. The only thing worth a moment is rebalancing the telescope, since 21.6oz at the back end will shift a light tube.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 5.5. A 1000mm telescope gives 182x and a 1200mm gives 218x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much sky does it show?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e57.3 multiplied by the 9.6mm field stop, divided by your focal length. At 1200mm that is about 0.46°, a little under the width of a full Moon — presented across a 100° apparent field, which is why it feels so much larger than the number suggests.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit a 1.25-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo, the barrel is 2.00″. For a 1.25-inch focuser at a similar magnification, the 82° Series LER designs are the ones to look at and we carry them.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e10.5mm of eye relief is on the shorter side for spectacle wearers. Observers who take their glasses off and focus the telescope instead get on well with it; if you keep glasses on, the 82° LER series carries more eye relief.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs the 100° field really different from 82°?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. At 82° the field edge is at the outer limit of a relaxed gaze; at 100° you turn your eye to find it. The practical effect at 218x is that an object stays in view noticeably longer on an undriven mount.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it need a special diagonal?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eA standard 2-inch diagonal is fine. Given the 612g weight, a diagonal with a compression ring rather than a single thumbscrew holds it more securely, and we stock those.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 612g, argon-purged 5.5mm eyepiece with a 100° apparent field, a 9.6mm field stop and a 2-inch barrel, sealed and tested to 1 metre for 30 minutes — the widest view Explore Scientific builds, at magnifications where a wide field does the most good. If you would like a second, longer focal length to pair with it for average nights, send us your telescope's focal length and we will suggest one that matches.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013054623855,"sku":"EPWP10055-01","price":415.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/55_medium__50117.jpg?v=1766548514"},{"product_id":"9mm-100-series-argon-purged-waterproof-eyepiece","title":"Explore Scientific 100° Series 9mm Argon-Purged Waterproof Eyepiece (2-Inch)","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 100° Series 9mm is a 2.00″ barrel ultra-wide-field eyepiece with 12.5mm of eye relief and a 15.7mm field stop. Published dimensions are 145mm long and 60mm wide, at 21.2oz; 602g. The housing is internally sealed and purged with argon gas, tested by submersion to one meter for 30 minutes, and the multi-coated optics use edge-blackened elements to hold contrast.\u003c\/p\u003e\n\u003cp\u003eAt 9mm this is a high-power eyepiece: 110x in a 988mm refractor, 135x in a 1216mm apochromat, 167x in a 1500mm Maksutov, 83x in a 750mm Newtonian. The 15.7mm field stop gives 0.91° of true field in a 988mm telescope and 0.74° in a 1216mm one.\u003c\/p\u003e\n\u003cp\u003eThe 100° apparent field is the defining figure. At that width the field edge falls outside the eye's natural attention, so the view reads as an open window rather than a circle with a boundary. Delivering it at 9mm is why the eyepiece carries a 2-inch barrel and 145mm of length despite a field stop small enough for a 1.25-inch fitting — the glass required to correct a 100° field at short focal length is simply large.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian owners observing at high power:\u003c\/strong\u003e 0.91° of true field at 110x is roughly double what a 50° eyepiece gives at the same magnification, and that is time before the target leaves the field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGlobular cluster and planetary nebula observers:\u003c\/strong\u003e 9mm resolves cluster cores and lifts small nebulae to a size worth studying, with sky to spare around them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar observers:\u003c\/strong\u003e at 135x in a 1216mm telescope, 0.74° of true field is wider than the Moon, so the whole disc sits inside a high-power view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who value immersion:\u003c\/strong\u003e this is the widest apparent field Explore Scientific builds.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDamp-site observers:\u003c\/strong\u003e the argon-purged, submersion-tested body is designed for dew and rain.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e100° apparent field of view:\u003c\/strong\u003e the widest in the Explore Scientific range, wide enough that the field stop sits at the edge of peripheral vision.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e15.7mm field stop:\u003c\/strong\u003e combined with 9mm of focal length, it produces a genuinely wide true field at high magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e12.5mm eye relief:\u003c\/strong\u003e the working figure for this design, and the reason the eyecup position matters when settling in at the eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2.00″ barrel:\u003c\/strong\u003e the fitting the optics require at this focal length and field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInternally sealed and argon gas purged,\u003c\/strong\u003e tested by submersion to one meter for 30 minutes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMulti-coated optics with edge-blackened elements:\u003c\/strong\u003e blackened edges stop light bouncing off the rim of a lens and scattering into the field, which is a real contrast issue in a wide-field design with large elements.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e145mm long, 60mm wide, 21.2oz; 602g:\u003c\/strong\u003e a large eyepiece by any measure, and the size is a direct consequence of the field.\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eBacked by a lifetime warranty on registration, with a 30-day return window.\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHigh-power deep-sky observing where field width keeps context around the target.\u003c\/li\u003e\n\u003cli\u003eGlobular clusters, planetary nebulae and compact galaxy groups.\u003c\/li\u003e\n\u003cli\u003eFull-disc lunar viewing at high magnification in medium focal length telescopes.\u003c\/li\u003e\n\u003cli\u003ePlanetary observing on steady nights, with room for the target to drift on an undriven mount.\u003c\/li\u003e\n\u003cli\u003eSweeping rich star fields at power, where the wide field turns a search into a scan.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocuser:\u003c\/strong\u003e the 2.00″ barrel fits 2-inch focusers and diagonals. There is no 1.25-inch path for it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 9. A 750mm Newtonian gives 83x; a 1216mm apochromat 135x; a 2000mm SCT 222x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 15.7 ÷ focal length × 57.3. A 750mm Newtonian yields 1.20°; a 2000mm SCT 0.45°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 9 ÷ focal ratio. An f\/5 Newtonian gives 1.8mm, an f\/6.5 refractor 1.38mm, an f\/10 SCT 0.9mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight and balance:\u003c\/strong\u003e 21.2oz; 602g at 145mm long is enough to change the balance of a Dobsonian or a small refractor noticeably. A magnetic counterweight or a friction adjustment on the altitude bearing handles it, and we stock counterweights.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocuser support:\u003c\/strong\u003e a 602g eyepiece cantilevered out of a focuser asks something of the focuser. A dual-speed or well-built single-speed unit carries it without sag.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e Explore Scientific does not publish a filter thread specification for this eyepiece, so that row is absent from the table below rather than estimated. If you plan to use a filter with it, ask us and we will check the thread with our Explore Scientific rep.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt needs a 2-inch focuser or diagonal.\u003c\/strong\u003e At 2.00″ the barrel has no 1.25-inch path. Telescopes with 1.25-inch focusers are better matched to the 82° Series at a similar focal length, which we stock and can suggest.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e12.5mm of eye relief with a 100° field asks for a settled eye position.\u003c\/strong\u003e The whole field comes in once the eye is placed correctly, and the adjustable eyecup is what makes that repeatable. Spectacle wearers generally find longer eye relief designs, such as the 68° and 72° ED Series, easier to use with glasses on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e21.2oz; 602g and 145mm of length change how a telescope balances.\u003c\/strong\u003e On a Dobsonian this is the single most common surprise, and it is solved inexpensively with a counterweight rather than by anything more involved.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFast focal ratios show their own coma at the edge of a 100° field.\u003c\/strong\u003e That is a property of the mirror rather than of the eyepiece, and a coma corrector addresses it directly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e9mm is a high-power focal length, so seeing conditions govern it.\u003c\/strong\u003e Steady nights reward it; turbulent ones favour a longer focal length. This is the eyepiece for the good nights.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count, coating designation or filter thread for this eyepiece,\u003c\/strong\u003e so those rows are absent below rather than estimated. Ask us if a particular figure matters and we will put it to our rep.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it goes into any 2-inch focuser or diagonal and is ready to use. The only practical step is rebalancing the telescope after fitting it, since at 21.2oz; 602g it is heavy enough to move the balance point on a light tube.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification and field will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eMagnification is your telescope's focal length divided by 9. True field is 15.7 divided by that focal length, multiplied by 57.3. A 1000mm telescope gives 111x and 0.90°.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy is a 9mm eyepiece this large?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eCorrecting a 100° apparent field at a short focal length takes a lot of glass, and that glass has to sit in a 2-inch barrel. The 145mm length and 602g weight are what the optical prescription costs.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e12.5mm of eye relief is tight for spectacle wearers who want the entire 100° field. If observing with glasses on is a requirement, the 68° and 72° ED Series carry more eye relief, and we can compare the true fields for your telescope.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill my focuser hold it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eMost 2-inch focusers will, though a 602g eyepiece is a real load on a light single-speed unit. Tell us your telescope and we will say whether the focuser is up to it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare to the 82° Series at a similar focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 100° shows a wider apparent field and a larger true field; the 82° is lighter, smaller and available in a 1.25-inch fitting. Focuser size and mount balance usually decide it — send us your setup and we will give you a straight answer.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 9mm, 2-inch, argon-purged eyepiece with a 100° apparent field, a 15.7mm field stop and 12.5mm of eye relief, submersion-tested to one meter for 30 minutes and backed by a lifetime warranty on registration — high power with an unusually wide field, in a 145mm, 602g body. If you would like us to work out the magnification, true field and balance implications for your telescope, send us its focal length and mount and we will run through it with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013055574127,"sku":"EPWP1009-01","price":415.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/9_medium__84515.jpg?v=1766548520"},{"product_id":"14mm-100-series-argon-purged-waterproof-eyepiece","title":"Explore Scientific 100° Series 14mm Argon-Purged Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 100° Series 14mm is the widest apparent field Explore Scientific builds: a 2-inch, argon-purged waterproof eyepiece with a 24.4mm field stop and 14.5mm of eye relief. It is fully multi-coated, fully sealed, and tested to withstand submersion to 1 metre for 30 minutes. Published dimensions are 157mm long, 70mm wide and 29.4 oz (836 g).\u003c\/p\u003e\n\u003cp\u003eAt 14mm the magnification is medium — 71x in a 1000mm telescope, 86x in a 1200mm SCT — but the field is not. The 24.4mm field stop gives 1.16° of true field at 1200mm and 2.91° at 480mm, and the 100-degree apparent field means that sky arrives as a view with no visible edge in ordinary use.\u003c\/p\u003e\n\u003cp\u003eThat is the trade this eyepiece makes: a 2-inch barrel and 836 g of glass and metal, in exchange for a field that keeps objects visible far longer without moving the telescope and gives averted vision somewhere to work.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers chasing immersion:\u003c\/strong\u003e at 100 degrees the field edge sits outside normal vision, so the view reads as sky rather than as a circle.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian owners:\u003c\/strong\u003e the wider the apparent field, the longer an object drifts before it needs a nudge — and at 14mm on an undriven mount that difference is substantial.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers\u003c\/strong\u003e working on nebulae and star fields where averted vision does the heavy lifting; more field gives the eye more room to wander across the object.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers with 2-inch focusers already fitted\u003c\/strong\u003e who want the widest apparent field available at a medium focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone observing in heavy dew or rain:\u003c\/strong\u003e the sealed, argon-purged body is tested to 1 metre for 30 minutes.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e100° apparent field of view:\u003c\/strong\u003e the widest in the Explore Scientific eyepiece range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e24.4mm field stop\u003c\/strong\u003e at a 14mm focal length — that combination is what produces the field, and it is why the barrel is 2 inches rather than 1.25.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e14.5mm eye relief,\u003c\/strong\u003e which is a workable eye position for a design of this apparent field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFully multi-coated optics,\u003c\/strong\u003e which matters more in a wide-field design because there are more surfaces in the path to lose light and contrast across.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon purged and fully sealed,\u003c\/strong\u003e tested to withstand submersion to 1 metre for 30 minutes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSubstantial build:\u003c\/strong\u003e 157mm long, 70mm wide, 29.4 oz (836 g).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConsistent within the 100° Series,\u003c\/strong\u003e so a set holds the same apparent field and eye position across focal lengths.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eDeep-sky observing on nebulae, galaxies and globular clusters at medium power.\u003c\/li\u003e\n\u003cli\u003eUndriven and Dobsonian observing, where apparent field is what buys time on target.\u003c\/li\u003e\n\u003cli\u003eLarge open clusters, where a wide field lets the whole group sit in surrounding sky.\u003c\/li\u003e\n\u003cli\u003eLunar observing, with the disc set inside an unusually large frame.\u003c\/li\u003e\n\u003cli\u003eObserving from damp, dew-heavy sites where a sealed eyepiece is the practical choice.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRequires a 2-inch focuser or diagonal.\u003c\/strong\u003e The 24.4mm field stop and the 100-degree field both need the larger barrel; there is no 1.25-inch equivalent of this combination.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length divided by 14. A 1200mm SCT gives 86x, a 900mm Newtonian gives 64x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 24.4 divided by focal length, times 57.3. A 1000mm telescope gives 1.40°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 14 divided by focal ratio — 2.3mm at f\/6 and 1.4mm at f\/10, both comfortable.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e takes standard 2-inch threaded filters. Oxygen-III and narrowband filters combine well with a wide field on large emission nebulae.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e 836 g at the focuser will move the balance point of a light tube. A counterweight or a small shift of the tube rings resolves it in one adjustment, and we stock counterweights for most tube styles.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt weighs 836 g and is 157mm long.\u003c\/strong\u003e A 2-inch focuser carries it without difficulty, though a lightweight refractor or a small Dobsonian will want rebalancing when it goes in. That is a one-time setup adjustment rather than an ongoing chore.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA 100-degree field is taken in by scanning, not by staring.\u003c\/strong\u003e The edge of the field sits beyond where the eye rests naturally, so you move your eye across the view. Observers new to the format usually settle into it within a session.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEye placement is more particular than in a narrower design.\u003c\/strong\u003e 14.5mm of eye relief gives room to work with, and once you find the position the fold-down eyecup makes it repeatable.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count for this eyepiece,\u003c\/strong\u003e so that row is absent below rather than estimated. If you would like the figure, ask and we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe submersion rating covers accidents, not use underwater.\u003c\/strong\u003e The 1 metre \/ 30 minute test is there so dew, rain and a drop into wet grass are non-events during a session.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 2-inch focuser or diagonal and is ready straight away. The one thing worth doing on the first night is rechecking your telescope's balance, since 836 g at the eyepiece end is enough to move it on a light tube.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification and true field will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eFocal length divided by 14 for magnification, and 24.4 divided by focal length times 57.3 for true field. A 1200mm SCT gives 86x over 1.16 degrees.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does a 100-degree field actually look like?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe field edge falls outside where your eye rests, so instead of looking at a bright circle you look into a scene. On a large open cluster or a nebula that changes how the object reads — it sits within surrounding sky rather than being framed by a hard boundary.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit a 1.25-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — the barrel is 2 inches. A 2-inch focuser or a 2-inch diagonal is what this eyepiece needs, and we stock diagonals for most telescope threads if yours is 1.25-inch only.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with the 82° Series at the same focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSame magnification, more field. The 82° 14mm has an 18.9mm field stop in a 256 g 1.25-inch body; this one has a 24.4mm field stop in an 836 g 2-inch body. You are trading weight and focuser size for a substantially larger true and apparent field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it suitable for astrophotography?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt is a visual eyepiece. Projection imaging with an adapter is possible, though a wide-field eyepiece of this kind is designed around what the eye takes in.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 14mm eyepiece with a 100° apparent field, a 24.4mm field stop and 14.5mm of eye relief, argon purged and tested to 1 metre for 30 minutes, in a 2-inch 836 g body — the widest apparent field Explore Scientific offers at a medium power. If you would like us to work out the true field it will give in your telescope, or how it would sit alongside the eyepieces you have, send us the details and we will do the arithmetic with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013056491631,"sku":"EPWP10014-01","price":484.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/14_medium__57014.jpg?v=1766548526"},{"product_id":"25mm-100-series-argon-purged-waterproof-eyepiece","title":"Explore Scientific 100° Series 25mm Argon-Purged Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 100° Series 25mm is a 2-inch argon-purged waterproof eyepiece with a 100-degree apparent field, a 41mm field stop and 14.5mm of eye relief. Explore Scientific publish its dimensions as 140mm long by 73mm wide and its weight as 41.5 oz (1177 g). It is item EPWP10025-01, and the housing is tested to withstand submersion at one metre for thirty minutes.\u003c\/p\u003e\n\u003cp\u003eA 41mm field stop is essentially the ceiling of the 2-inch format. True field is field stop divided by telescope focal length, expressed in degrees: 2.35° in a 1000mm telescope, 2.38° in a 988mm f\/6.5 refractor, 1.24° in a 1900mm Maksutov. At 40x in a metre-class instrument, that is well over four full-Moon diameters of sky at once — and it is delivered inside a 100-degree apparent field, which is wide enough that the field edge sits outside the range the eye scans without turning.\u003c\/p\u003e\n\u003cp\u003eThe exit pupil is 25 divided by the telescope's focal ratio: 5mm at f\/5, 3.8mm at f\/6.5, 2.5mm at f\/10. In a fast telescope that is a large exit pupil, which is what makes low-power ultra-wide observing under a dark sky so effective — the eye receives a bright, wide, well-filled beam.\u003c\/p\u003e\n\u003cp\u003eExplore Scientific also note that the wide field makes objects easier to locate and keeps them in view longer, and that the design supports averted vision, where looking slightly to one side of a faint object brings it out.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDark-site deep-sky observers:\u003c\/strong\u003e 2.35° of true field in a metre-focal-length telescope covers the North America Nebula, the Veil complex and the largest open clusters in single views.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who want immersion:\u003c\/strong\u003e at 100 degrees the field boundary is outside normal peripheral scanning, which is what removes the sense of looking down a tube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian users:\u003c\/strong\u003e the widest apparent field available buys the longest drift time between nudges, which matters most at the eyepiece you use for finding and framing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers hunting faint extended objects:\u003c\/strong\u003e a large exit pupil and a clean, wide field are the two things averted vision needs in order to work.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone observing in heavy dew:\u003c\/strong\u003e the argon-purged body is rated for a metre of water for half an hour, so dew and rain are not events.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e100° apparent field of view:\u003c\/strong\u003e the widest apparent field Explore Scientific build, and the defining characteristic of the eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e41mm field stop:\u003c\/strong\u003e at or very near the physical maximum a 2-inch barrel can pass, which is what turns the apparent field into real sky.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e25mm focal length:\u003c\/strong\u003e 40x in a 1000mm telescope, 76x in a 1900mm one — a low-to-medium power step.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e14.5mm eye relief:\u003c\/strong\u003e the published figure, workable for most observers though snug for a wide field of this size.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged and sealed:\u003c\/strong\u003e tested at one metre depth for thirty minutes. Dry argon inside carries no moisture to condense on cooling glass.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFully multi-coated:\u003c\/strong\u003e anti-reflection coatings across the optical surfaces, which matters a great deal in a design with this many air-to-glass interfaces.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e140mm long, 73mm wide, 41.5 oz (1177 g):\u003c\/strong\u003e a large and heavy ocular, which is what an ultra-wide field at 25mm costs in glass.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSupports averted vision:\u003c\/strong\u003e Explore Scientific describe the field as clean enough to let the observer look beside a faint target while it stays comfortably in the view.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eWide-field deep-sky observing from a dark site — large nebulae, star fields and the biggest open clusters.\u003c\/li\u003e\n\u003cli\u003eSweeping the summer Milky Way, where 2.35° of true field is the whole point.\u003c\/li\u003e\n\u003cli\u003eLocating and framing objects before switching to a higher-power eyepiece.\u003c\/li\u003e\n\u003cli\u003eComet observing, where the coma and tail need generous room.\u003c\/li\u003e\n\u003cli\u003eUndriven and Dobsonian observing at the widest field the telescope can deliver.\u003c\/li\u003e\n\u003cli\u003eDamp and dew-heavy sites where a sealed, gas-purged eyepiece keeps working.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e2-inch focusers and diagonals only.\u003c\/strong\u003e A 41mm field stop cannot pass through a 1.25-inch barrel, so the format is set by the optics.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 41 divided by your telescope's focal length in millimetres, multiplied by 57.3. A 1200mm SCT yields 1.96°; a 750mm Newtonian yields 3.13°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length divided by 25. A 650mm refractor gives 26x, a 1500mm gives 60x, a 2000mm gives 80x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e the 2-inch barrel takes standard 2-inch threaded filters. A wide field and an O-III or broadband nebula filter is one of the most productive combinations in visual astronomy.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocuser strength:\u003c\/strong\u003e 41.5 oz is a lot of mass cantilevered off a focuser drawtube. Rack-and-pinion and quality Crayford focusers handle it; older or lighter focusers can slip under it, and tightening the drawtube tension screw is the usual first adjustment.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e on a Dobsonian this eyepiece will tip the tube. Magnetic balance weights or a spring-tensioned altitude bearing solve it, and we can supply the weights.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt weighs 41.5 oz (1177 g).\u003c\/strong\u003e That is heavier than many finder scopes, and it will change the balance of most telescopes and load the focuser noticeably. Counterweights and focuser tension adjustments handle it, and we can put the right weight in the box with it if you tell us what you are fitting it to.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e14.5mm of eye relief with a 100-degree field means eye placement matters.\u003c\/strong\u003e There is a position where the whole field appears at once, and finding it takes a moment at first. The eyecup is what makes that position repeatable once you have it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is 140mm long and 73mm wide.\u003c\/strong\u003e Some eyepiece cases and most binoviewers will not take an ocular of that size, so a case with deep compartments is worth planning for.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFast telescopes place more demand on the outer field.\u003c\/strong\u003e At f\/4 or f\/4.5, coma from the telescope itself becomes visible near the edge of a field this wide — that comes from the primary mirror rather than the eyepiece, and a coma corrector is the answer. We stock them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish the element count for this model,\u003c\/strong\u003e so that row is absent below rather than estimated. If you want it for a comparison, we can ask our Explore Scientific rep.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. It goes into a 2-inch focuser or diagonal and works immediately. The two practical steps are tightening the focuser drawtube enough to hold 41.5 oz securely and rebalancing the telescope afterwards.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much sky does it show?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 41mm field stop gives 2.35° of true field in a 1000mm telescope at 40x — more than four full-Moon diameters. In a 1500mm telescope it is 1.57° at 60x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy is it so heavy?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eA 100-degree apparent field at 25mm requires large-diameter elements and a lot of them. The 73mm body width and the 41.5 oz weight are what that optical prescription weighs in glass and metal.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it in a 1.25-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — the 41mm field stop is wider than a 1.25-inch barrel. This eyepiece is 2-inch only.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does the argon purging achieve?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe internal air is replaced with dry argon and the housing is sealed, which is why it survives a metre of water for thirty minutes. In routine use the benefit is that the inside never fogs as the eyepiece cools past the dew point.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with the 82° Series?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 100° Series gives a wider apparent field and, at 25mm, a larger field stop and therefore more true sky. The 82° designs are lighter and easier on eye placement. Tell us what telescope it is going on and we will tell you which trade is the better one in your case.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 25mm eyepiece with a 100-degree apparent field, a 41mm field stop at the practical limit of the 2-inch format, 14.5mm of eye relief and an argon-sealed body rated to a metre of water — the widest view Explore Scientific offer at this focal length. If you would like to know how much sky it will show in your telescope, and whether your focuser will hold 41.5 oz comfortably, send us the details and we will work it through with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013058261103,"sku":"EPWP10025-01","price":1246.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/25_medium__39410.jpg?v=1766548533"},{"product_id":"30mm-100-series-argon-purged-waterproof-eyepiece","title":"Explore Scientific 100° Series 30mm 3-Inch Argon-Purged Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 100° Series 30mm is the hyper-wide, low-power flagship of the range, and it is built on a 3-inch barrel rather than the 2-inch format most eyepieces use. That barrel size is the whole story: a 100° apparent field at 30mm needs a field stop larger than a 2-inch tube can physically pass, so the eyepiece steps up to a format that can carry it.\u003c\/p\u003e\n\u003cp\u003eThe construction is argon purged and internally sealed, fully multi-coated for contrast, and waterproof-tested to 1 metre of depth for 30 minutes. Explore Scientific describes the observing experience as panoramic, and specifically calls out how well the very large field supports extended study of faint objects using averted vision — the technique of looking slightly off-centre so the target falls on the more light-sensitive part of the retina. A 100° field gives that technique room to work in a way a narrow field does not.\u003c\/p\u003e\n\u003cp\u003eExplore Scientific publishes no dimensional specification table for this eyepiece. Eye relief, field stop diameter, element count, physical size and weight are all absent from their product page, so those rows read as unpublished below rather than carrying figures we have inferred from elsewhere. What is published — focal length, apparent field, barrel format, sealing and waterproof rating — is given verbatim.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDark-site deep-sky observers\u003c\/strong\u003e who want the largest possible expanse of sky at once, with a fully dark-adapted eye and no light pollution to waste the exit pupil on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who work faint objects with averted vision:\u003c\/strong\u003e a 100° field gives the eye somewhere to go, which is precisely what the technique needs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOwners of large Dobsonians and premium refractors\u003c\/strong\u003e already equipped with a 3-inch focuser or diagonal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone observing in dew, frost or humidity:\u003c\/strong\u003e argon purging and a 1-metre, 30-minute waterproof rating are built for weather rather than for marketing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e100° apparent field of view:\u003c\/strong\u003e beyond the limit of comfortable direct vision, so the field edge sits in peripheral vision and the view reads as a window onto the sky rather than a circle of light.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e30mm focal length:\u003c\/strong\u003e low power in most telescopes, which is what keeps the exit pupil large and the field genuinely wide.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e3-inch barrel:\u003c\/strong\u003e the format required to pass a field stop this large. It is what makes a 100° field at 30mm physically possible.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon purged and internally sealed:\u003c\/strong\u003e dry inert gas inside the housing rather than ambient air, so internal fogging is not a failure mode and humidity cannot migrate in over the years.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFully multi-coated optics\u003c\/strong\u003e for transmission and contrast, which is where a low-power deep-sky eyepiece earns its keep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof-tested to 1 metre for 30 minutes:\u003c\/strong\u003e a published, specific rating rather than a general claim.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBacked by a limited warranty\u003c\/strong\u003e and a 30-day return guarantee when returned in original condition.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eWide-field deep-sky observing from a dark site — Milky Way star fields, large emission nebulae, extended supernova remnants.\u003c\/li\u003e\n\u003cli\u003eFraming objects too large for a conventional field: the Veil complex, the North America Nebula, the Pleiades with their surrounding field.\u003c\/li\u003e\n\u003cli\u003eLow-power sweeping in a large Dobsonian, where the wide apparent field also lengthens the time an object stays in view.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eA 3-inch focuser or diagonal is required.\u003c\/strong\u003e This is the central compatibility question for this eyepiece, and it is worth settling before anything else. Send us your telescope make and model and we will tell you what it takes to accept a 3-inch eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 30. A 1200mm telescope gives 40x; a 1500mm gives 50x; a 2000mm gives 67x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 30mm divided by your telescope's focal ratio. At f\/4 that is 7.5mm, at f\/5 it is 6mm, at f\/10 it is 3mm. In very fast telescopes part of that cone can fall outside a dark-adapted pupil, which is worth thinking about when matching this focal length to a fast instrument.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e set by the field stop diameter, which Explore Scientific does not publish for this eyepiece. Apparent field divided by magnification gives a close working figure, and we can get the exact number from our Explore Scientific rep if it matters to you.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e the 3-inch format is not the usual filter thread size, so a nebula filter is more often placed elsewhere in the light path. Tell us how your focuser and diagonal are arranged and we will work out where a filter fits in your setup.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e a 3-inch eyepiece is a substantial object, and it will shift the balance of most telescopes when inserted. Counterweights and adjustable rings are the standard remedy and we stock them.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 3-inch barrel is the deciding factor.\u003c\/strong\u003e It needs a focuser or diagonal with a 3-inch receiver, and that is a less common fitting than 2-inch. Before you order, send us the telescope you plan to use it in and we will tell you exactly what is involved.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific publishes no dimensional specifications for this eyepiece.\u003c\/strong\u003e Eye relief, field stop, element count, size and weight are absent from their product page, so those rows below are marked unpublished rather than estimated. If any of them decides the purchase for you, ask and we will put the question to our Explore Scientific rep before you commit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e100° is best appreciated under a dark sky.\u003c\/strong\u003e Under heavy light pollution a large exit pupil mostly delivers more sky glow; the same eyepiece at a dark site is a completely different experience. A broadband or nebula filter helps from town.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof covers weather, not use underwater.\u003c\/strong\u003e The 1 metre \/ 30 minute test exists so that dew, rain and a dropped eyepiece in wet grass are recoverable events rather than expensive ones.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe eyepiece itself takes no setting up — it slides into a 3-inch focuser or diagonal and is ready. The preparation happens before it arrives: your telescope needs a 3-inch receiver, and the balance is worth resetting once the eyepiece is in place. Tell us what you are using and we will settle the fitting side with you ahead of time.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy a 3-inch barrel?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eField stop diameter sets the true field, and a 100° apparent field at 30mm calls for a field stop larger than a 2-inch barrel can pass. The 3-inch format exists to carry it. It is the reason this eyepiece can do something a 2-inch eyepiece physically cannot.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit my telescope?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThat depends on whether your focuser or diagonal takes 3-inch accessories. Some large Dobsonians and premium refractors do, and others can be upgraded. Send us the make and model and we will give you a straight answer.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 30. A 1500mm telescope gives 50x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow wide is the true field?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExplore Scientific does not publish the field stop diameter, so we would rather not quote a precise number. Dividing 100° by your magnification gives a close approximation, and we can obtain the exact figure from our rep on request.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it worth it under a suburban sky?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSome of the benefit is spent on sky glow at a low-power focal length. A nebula filter recovers a good deal of it, and the eyepiece comes into its own at a dark site. If your observing is mostly from town, it is worth a conversation about whether a shorter focal length in the series would serve you better.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 30mm eyepiece with a 100° apparent field on a 3-inch barrel, argon purged, fully multi-coated and waterproof-tested to 1 metre for 30 minutes — the panoramic low-power view, in the format that makes it possible. The fitting question is the one worth settling first, so send us your telescope model and we will confirm what it takes to run a 3-inch eyepiece in it.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013059440751,"sku":"EPWP10030-01","price":1745.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/30_medium__48363.jpg?v=1766548539"},{"product_id":"20mm-100-series-argon-purged-waterproof-eyepiece","title":"Explore Scientific 100° Series 20mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 100° Series 20mm is a large 2-inch waterproof eyepiece built around a 100-degree apparent field, with a published field stop of 34.8mm and 14.5mm of eye relief. The body is 156mm long and 70mm wide, and Explore Scientific's current figure for its weight is 916 g.\u003c\/p\u003e\n\u003cp\u003eThe 34.8mm field stop is close to the practical limit of what a 2-inch barrel can pass, which is what makes this eyepiece interesting: at 20mm it combines a wide true field with enough magnification to darken the sky background. In a 714mm refractor that works out to 36x over 2.79°; in a 1000mm telescope, 50x over 1.99°; in a 1200mm Schmidt-Cassegrain, 60x over 1.66°.\u003c\/p\u003e\n\u003cp\u003eThe optics are fully multi-coated and edge-blackened, and the housing is gas-purged and tested to one metre of submersion for thirty minutes.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers chasing large objects:\u003c\/strong\u003e the North America Nebula, the Veil, the Heart and Soul complexes and the largest open clusters all fit inside a 2.79° field in a short-focus telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who want the spacewalk view:\u003c\/strong\u003e at 100 degrees the field edge sits outside the eye's normal attention, so there is no sense of looking down a tube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven-mount users:\u003c\/strong\u003e more apparent field means more drift time between nudges, and at 100° that is a substantial gain.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who want one eyepiece to do the low-power work:\u003c\/strong\u003e at 20mm this covers finding, framing and sweeping in a single ocular.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDamp-site observers:\u003c\/strong\u003e the sealed, gas-purged housing and the 1 metre \/ 30 minute submersion test are built for weather that ends other sessions.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e100° apparent field of view:\u003c\/strong\u003e the widest apparent field Explore Scientific offers, which is what produces the impression of an unframed view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e34.8mm field stop:\u003c\/strong\u003e a published figure near the ceiling for a 2-inch barrel, and the number that fixes the true field precisely.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e14.5mm eye relief,\u003c\/strong\u003e notably generous for a 100-degree design where eye relief is usually the hardest constraint.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFully multi-coated and edge-blackened elements:\u003c\/strong\u003e the coatings raise transmission and the blackened edges suppress the internal reflections that a large, many-element eyepiece is otherwise prone to.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGas-purged sealed housing,\u003c\/strong\u003e submersion tested to 1 metre for 30 minutes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2-inch barrel\u003c\/strong\u003e accepting standard 2-inch threaded filters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished dimensions:\u003c\/strong\u003e 156mm long, 70mm wide, 916 g on the current Explore Scientific spec sheet.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eWide-field deep-sky observing of large nebulae, star clouds and open clusters.\u003c\/li\u003e\n\u003cli\u003eLow-power sweeping of the Milky Way, where 100 degrees of field is at its most striking.\u003c\/li\u003e\n\u003cli\u003eFinding and framing before switching to higher power on the same target.\u003c\/li\u003e\n\u003cli\u003eNebula-filter observing, where the wide true field and a 2-inch narrowband filter work together.\u003c\/li\u003e\n\u003cli\u003eLong sessions on an undriven mount, where the apparent field keeps objects in view.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRequires a 2-inch focuser or diagonal\u003c\/strong\u003e with enough clearance for a 156mm long, 70mm wide body. Tell us your focuser and diagonal and we will check the clearance with you.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 20. A 714mm refractor gives 36x, a 1000mm gives 50x, a 1200mm SCT gives 60x, a 1500mm Maksutov gives 75x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 34.8 ÷ focal length × 57.3. That is 2.79° at 714mm, 1.99° at 1000mm, 1.66° at 1200mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 20mm divided by the telescope's focal ratio — 4.0mm at f\/5, 2.9mm at f\/7, 2.0mm at f\/10. All comfortable sizes for a dark-adapted eye.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e standard 2-inch threaded filters. A broadband or narrowband nebula filter is the natural companion given the field size.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e 916 g is a substantial mass at the focuser. Magnetic balance weights or a counterweight bar settle a Dobsonian that tips with it in place, and we stock both.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis is a large, heavy eyepiece.\u003c\/strong\u003e 156mm long, 70mm wide and 916 g is enough to unbalance a lightly loaded Dobsonian or a small refractor on a photo tripod. Balance weights fix it, and we can include one with the order.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific has published two weight and purge figures across revisions.\u003c\/strong\u003e The current sheet for item EPWP10020-01 lists 916 g and describes the housing as argon-purged; an earlier sheet for item EPWP10020-00 listed 968 g and described it as nitrogen-purged. Both are shown as published rather than reconciled into one number.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA focuser needs clearance for the body.\u003c\/strong\u003e At 70mm wide the eyepiece can foul a finder bracket or a low-profile focuser on some telescopes. Send us your telescope model and we will check it before you order.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA 100° field asks the eye to travel.\u003c\/strong\u003e Seeing the whole field means looking around it, and the outer few degrees sit beyond where the eye naturally rests. That is what the design is for rather than a shortcoming.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe submersion rating covers immersion, not use underwater.\u003c\/strong\u003e 1 metre for 30 minutes is there so heavy dew, rain and a drop in wet grass are non-events.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count\u003c\/strong\u003e for this eyepiece, so that row is absent below rather than estimated.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 2-inch focuser or diagonal and is ready to observe with. The only thing worth a moment's thought is balance: at 916 g it may shift a light telescope enough to want a counterweight.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat true field will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide 34.8 by your telescope's focal length in millimetres and multiply by 57.3. A 1000mm telescope gives 1.99°; a 1500mm gives 1.33°.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes the 100-degree field really look different?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, distinctly. At 82° the field edge is still within peripheral awareness; at 100° it falls outside it, so the view reads as sky rather than as a circle. It is the single most-remarked difference between the two series.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use a nebula filter with it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. Standard 2-inch threaded filters thread into the barrel, and a wide true field is exactly where narrowband filters show their value on large emission nebulae.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it balance on my Dobsonian?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt depends on the telescope and what else is on the tube. 916 g at the focuser is enough to tip a light Dob forward, and magnetic weights on the lower tube correct it. Tell us the model and we will give you a straight answer.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much eye relief is there?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e14.5mm, which is generous for a 100-degree design and enough that most observers find long sessions comfortable.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 20mm eyepiece with a 100° apparent field, a 34.8mm field stop, 14.5mm of eye relief and a sealed 2-inch body tested to 1 metre for 30 minutes — the widest true field this focal length can deliver through a 2-inch barrel. If you would like the exact true field and exit pupil for the telescope you own, send us its aperture and focal length and we will work them out with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013216956527,"sku":"EPWP10020-01","price":692.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/20_medium__63241.jpg?v=1766548852"},{"product_id":"24mm-68-deg-eyepiece","title":"Explore Scientific 68° Series 24mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 68° Series 24mm is the eyepiece that extracts the widest true field a 1.25-inch barrel can physically deliver. Its published field stop is 27.2mm, and a 1.25-inch barrel has an internal diameter of about 28mm — so this design is working right up against the mechanical limit of the format. Nothing in a 1.25-inch barrel shows more sky at once.\u003c\/p\u003e\n\u003cp\u003eThe other published figures are 24mm focal length, 18.4mm eye relief, a body 75.6mm long and 56.2mm wide, and a weight of 11.6oz (329g). Explore Scientific describes the optical design as using combinations of low-dispersion and high-refractive-index glasses arrived at by computer optimisation, in an argon-purged housing that resists internal fogging and contamination, tested for waterproofness at one metre of water for thirty minutes. A removable, foldable silicone rubber eyecup is supplied.\u003c\/p\u003e\n\u003cp\u003eThe 68° apparent field sits a clear step above the 52° and 62° designs and below the 82° and 92° ranges — wide enough to feel open at the eye without the outer-field demands a 100-degree-class design places on a fast telescope.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who want the widest 1.25-inch true field available:\u003c\/strong\u003e at a 27.2mm field stop this is the practical ceiling of the format, and moving wider means moving to 2-inch eyepieces and a 2-inch focuser.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 18.4mm of eye relief is generous by any standard, and the foldable eyecup rolls back so spectacle lenses can sit close enough to take in the whole 68°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven-mount users:\u003c\/strong\u003e a wide apparent field is time on target when nothing is tracking, and at 24mm the drift is slow to begin with.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers\u003c\/strong\u003e framing open clusters, large nebulae and rich Milky Way fields.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers in damp conditions:\u003c\/strong\u003e the argon-purged, sealed housing is specified against internal fogging and contamination.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e27.2mm field stop:\u003c\/strong\u003e the largest field stop that fits a 1.25-inch barrel, and the figure that fixes the true field exactly — 57.3 × 27.2 ÷ your telescope's focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e68° apparent field:\u003c\/strong\u003e noticeably more open than a 52° or 62° design, without asking as much of the outer field as an 82° or 92° eyepiece does.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e18.4mm eye relief:\u003c\/strong\u003e among the more generous figures published at this focal length, which is what makes observing with glasses on comfortable rather than merely possible.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow-dispersion and high-refractive-index glasses\u003c\/strong\u003e in a computer-optimised combination, which is how a wide apparent field is corrected across the whole of the view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged construction:\u003c\/strong\u003e argon rather than air inside the body means no internal condensation and no airborne contamination reaching the internal surfaces.\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eWaterproof, tested at one metre of water for 30 minutes.\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ barrel:\u003c\/strong\u003e fits any standard 1.25-inch focuser or diagonal directly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemovable, foldable silicone rubber eyecup:\u003c\/strong\u003e up for observing without glasses, folded down for observing with them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e75.6mm long, 56.2mm wide, 11.6oz (329g):\u003c\/strong\u003e a substantial 1.25-inch eyepiece, and the 56.2mm body diameter is what makes the wide eye lens possible.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eWidest-field low-power observing in a telescope with only a 1.25-inch focuser.\u003c\/li\u003e\n\u003cli\u003eOpen clusters, large emission nebulae and Milky Way sweeping.\u003c\/li\u003e\n\u003cli\u003eFraming large objects that overflow a narrower field — the Pleiades, the Double Cluster, the Veil.\u003c\/li\u003e\n\u003cli\u003eObserving with glasses on, where the 18.4mm eye relief is the deciding specification.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal.\u003c\/strong\u003e In a 2-inch focuser it takes a 2-inch to 1.25-inch adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 24. A 663mm refractor gives 28x, a 1219mm Dobsonian 51x, a 2000mm Schmidt-Cassegrain 83x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 57.3 × 27.2 ÷ telescope focal length — 2.35° at 663mm, 1.28° at 1219mm, 0.78° at 2000mm. That is more than four full-Moon widths in a short refractor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 24 ÷ the telescope's focal ratio. An f\/5.9 Dobsonian gives 4.1mm, an f\/6.5 refractor 3.7mm, an f\/10 Schmidt-Cassegrain 2.4mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e takes standard 1.25-inch threaded filters. A narrowband nebula filter and a wide-field 24mm is one of the more productive combinations in visual deep-sky observing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e at 329g this is heavier than a simple 1.25-inch eyepiece. On a small refractor or a Dobsonian it is worth rechecking balance after swapping to it, which usually means sliding a tube in its rings or adjusting the tension on a Dobsonian base.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eA 1.25-inch barrel caps how wide the true field can go,\u003c\/strong\u003e and this eyepiece is already at that cap. Going wider means a 2-inch focuser and a 2-inch eyepiece — there is no 1.25-inch design that gets past a field stop of roughly 27mm. If your telescope has a 2-inch focuser and you want more field, we can show you what the 2-inch options give.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish the element count, the group count or the coating specification\u003c\/strong\u003e for this eyepiece. Those rows read as not published in the table below rather than being estimated. If a specific figure decides the purchase for you, ask us and we will put it to our Explore Scientific representative.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a physically large eyepiece:\u003c\/strong\u003e 75.6mm long, 56.2mm across and 329g. In a short focuser drawtube or a compact case, the length is worth measuring; in a Dobsonian, the mass is worth allowing for in balance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIn a fast telescope the exit pupil grows.\u003c\/strong\u003e Below about f\/4.5, 24mm produces an exit pupil wider than most dark-adapted eyes open to, so a shorter focal length uses the aperture better. Tell us your focal ratio and we will suggest where the sweet spot sits.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe waterproof rating covers immersion, not use underwater.\u003c\/strong\u003e It exists so that dew, rain and an eyepiece dropped in wet grass are not what ends a session.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 1.25-inch focuser or diagonal and is ready immediately. The eyecup folds by hand and there is nothing to assemble or align.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 24. A 1000mm telescope gives 42x; a 1219mm Dobsonian gives 51x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy does the 27.2mm field stop matter?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eBecause it, not the apparent field, is what fixes how much sky you see. True field equals 57.3 multiplied by 27.2 and divided by your telescope's focal length. At 27.2mm this eyepiece is at the physical limit of the 1.25-inch format, so no other 1.25-inch eyepiece shows more sky in the same telescope.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, and comfortably. 18.4mm of eye relief with a foldable eyecup is enough for most spectacle wearers to take in the full 68°.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with the 82° Series at a similar focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 82° designs give a wider, more enveloping apparent field. The 68° here is built around a maximum-diameter field stop and long eye relief in the smaller barrel size. In a 1.25-inch-only telescope the 68° 24mm is the wider true field of the two; in a 2-inch focuser the comparison changes. Tell us which telescope it is going into and we will give you a straight answer.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it work in my Dobsonian?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, and the wide apparent field is particularly useful on an undriven mount because objects take longer to cross it. At 329g it is worth a quick balance check after swapping eyepieces.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 24mm argon-purged waterproof eyepiece with a 68° apparent field, 18.4mm of eye relief and a 27.2mm field stop — the maximum true field the 1.25-inch format allows, in a housing built to shrug off dew. If you are working out where it fits alongside eyepieces you already own, send us your telescope's focal length and the focal lengths in your case and we will map the gaps.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013286424687,"sku":"EPWP6824-01","price":151.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/esepwp682401__39958.jpg?v=1766550512"},{"product_id":"16mm-68-deg-eyepiece","title":"Explore Scientific 16mm 68 deg Eyepiece","description":"\u003cp style=\"margin:0in;margin-bottom:.0001pt;line-height:13.5pt;background:white\"\u003e\u003cspan style=\"font-size: 11pt; font-family: Arial, sans-serif; color: rgb(34, 34, 34); background-image: initial; background-attachment: initial; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;\"\u003eUsing advanced computer design, combinations of low dispersion and high refractive index optical glasses, and durable multilayer deposition coatings, Explore Scientific 68° Series  Argon-Purged Waterproof extreme wide field eyepieces are optimized to produce high contrast, high resolution, and superior flat field characteristics. The visual effect of these eyepieces with their long eye-relief and their 68° apparent field is truly a full-immersion experience. The 68° Series eyepieces come with a removable and foldable soft silicone rubber eyecup for the comfort of the observer, and as experienced astronomers know, eye comfort is critical when trying to observe at the visual limits of the telescope.\u003co:p\u003e\u003c\/o:p\u003e\u003c\/span\u003e\u003c\/p\u003e  \u003cp style=\"margin:0in;margin-bottom:.0001pt;line-height:13.5pt;background:white\"\u003e\u003cspan style=\"color: rgb(34, 34, 34); font-family: Arial, sans-serif; line-height: 13.5pt;\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin:0in;margin-bottom:.0001pt;line-height:13.5pt;background:white\"\u003e\u003cspan style=\"color: rgb(34, 34, 34); font-family: Arial, sans-serif; line-height: 13.5pt;\"\u003eProtection from the Outdoors - By making the eyepiece body Argon-purged, the waterproof eyepiece internal elements will remain as pristine as the day they were assembled.\u003c\/span\u003e\u003c\/p\u003e  \u003cp class=\"MsoNormal\" style=\"margin-bottom:0in;margin-bottom:.0001pt;line-height: 13.5pt;background:white\"\u003e\u003cspan style=\"font-family: Arial, sans-serif; color: rgb(34, 34, 34); background-image: initial; background-attachment: initial; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;\"\u003eArgon atoms are   larger  than that of Nitrogen and therefore they are less likely to  leak  or diffuse their way through the seals over the life of the eyepiece. The atomic radius of Argon is larger than Nitrogen by 0.13 angstroms and has a larger atomic volume by 11.2 cubic centimeters\/molecule. Argon also has superior inertness vs Nitrogen (i.e. forming few or no chemical compounds with other elements) that prevents adverse reactions with eyepiece components and therefore extends the longevity of the internal components, and also prevents chemical reactions with other elemental contaminants that may be introduced through a weakened seal. And, finally because Argon is less conductive of heat than Nitrogen, Argon cools slower thereby buffering the effects of rapid temperature changes of the optics.\u003co:p\u003e\u003c\/o:p\u003e\u003c\/span\u003e\u003c\/p\u003e  \u003cp class=\"MsoNormal\" style=\"margin-bottom:0in;margin-bottom:.0001pt;line-height: 13.5pt;background:white\"\u003e\u003cspan style=\"font-family: Arial, sans-serif; color: rgb(34, 34, 34); background-image: initial; background-attachment: initial; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;\"\u003e\u003co:p\u003e \u003c\/o:p\u003e\u003c\/span\u003e\u003cspan style=\"color: rgb(34, 34, 34); font-family: Arial, sans-serif; line-height: 13.5pt;\"\u003eThe sealed, dry environment is impervious to internal fogging and contaminants such as fungus growing in between the lens elements. Our waterproof eyepiece is easier to clean, and there is no risk of cleaning solution migrating from the top of the lens and seeping around edges to be trapped in between elements. To insure a perfect seal we test every eyepiece in one meter of water for 30 minutes.\u003c\/span\u003e\u003c\/p\u003e\u003ctable class=\"data-table\" id=\"product-attribute-specs-table\" style=\"box-sizing: border-box; margin: 0px; padding: 0px; border-collapse: collapse; border-spacing: 0px; font-family: 'Open Sans', Arial, sans-serif; color: rgb(99, 99, 99); font-size: 14px; line-height: 21px; width: 700px; max-width: 50em; border: 1px solid silver; background-color: rgb(255, 255, 255);\"\u003e\u003ctbody style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003ctr class=\"first odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eSKU\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eES-EPWP6816-01\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eMANUFACTURER\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eExplore Scientific\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eOPTICAL DESIGN\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eWide Angle\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eBARREL SIZE\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eWARRANTY\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eLifetime Warranty\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eEYEPIECE FIELD OF VIEW - APPARENT\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e68º\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eEYEPIECE FOCAL LENGTH\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e16mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eEYEPIECE EYE RELIEF\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e11.9mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eEYEPIECE MANUFACTURER SERIES\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eExplore Scientific 68º Waterproof\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eEYEPIECE WEIGHT\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e5.5oz, 158g\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eFIELD STOP\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e18.2mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eNUMBER OF LENS ELEMENTS \u0026amp; GROUPS\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e7 elements in 4 groups\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eSPECIAL FEATURE\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eWaterproof\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eCOMES WITH DUST CAPS?\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"last odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eCOMES WITH EYE GUARD?\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013287440495,"sku":"EPWP6816-01","price":151.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/16_1024x1024__61719.jpg?v=1766550518"},{"product_id":"20mm-68-deg-eyepiece","title":"Explore Scientific 20mm 68 deg Eyepiece","description":"\u003cp style=\"margin:0in;margin-bottom:.0001pt;line-height:13.5pt;background:white\"\u003e\u003cspan style=\"font-size: 11pt; font-family: Arial, sans-serif; color: rgb(34, 34, 34); background-image: initial; background-attachment: initial; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;\"\u003eUsing advanced computer design, combinations of low dispersion and high refractive index optical glasses, and durable multilayer deposition coatings, Explore Scientific 68° Series  Argon-Purged Waterproof extreme wide field eyepieces are optimized to produce high contrast, high resolution, and superior flat field characteristics. The visual effect of these eyepieces with their long eye-relief and their 68° apparent field is truly a full-immersion experience. The 68° Series eyepieces come with a removable and foldable soft silicone rubber eyecup for the comfort of the observer, and as experienced astronomers know, eye comfort is critical when trying to observe at the visual limits of the telescope.\u003co:p\u003e\u003c\/o:p\u003e\u003c\/span\u003e\u003c\/p\u003e  \u003cp style=\"margin:0in;margin-bottom:.0001pt;line-height:13.5pt;background:white\"\u003e\u003cspan style=\"color: rgb(34, 34, 34); font-family: Arial, sans-serif; line-height: 13.5pt;\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin:0in;margin-bottom:.0001pt;line-height:13.5pt;background:white\"\u003e\u003cspan style=\"color: rgb(34, 34, 34); font-family: Arial, sans-serif; line-height: 13.5pt;\"\u003eProtection from the Outdoors - By making the eyepiece body Argon-purged, the waterproof eyepiece internal elements will remain as pristine as the day they were assembled.\u003c\/span\u003e\u003c\/p\u003e  \u003cp class=\"MsoNormal\" style=\"margin-bottom:0in;margin-bottom:.0001pt;line-height: 13.5pt;background:white\"\u003e\u003cspan style=\"font-family: Arial, sans-serif; color: rgb(34, 34, 34); background-image: initial; background-attachment: initial; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;\"\u003eArgon atoms are   larger  than that of Nitrogen and therefore they are less likely to  leak  or diffuse their way through the seals over the life of the eyepiece. The atomic radius of Argon is larger than Nitrogen by 0.13 angstroms and has a larger atomic volume by 11.2 cubic centimeters\/molecule. Argon also has superior inertness vs Nitrogen (i.e. forming few or no chemical compounds with other elements) that prevents adverse reactions with eyepiece components and therefore extends the longevity of the internal components, and also prevents chemical reactions with other elemental contaminants that may be introduced through a weakened seal. And, finally because Argon is less conductive of heat than Nitrogen, Argon cools slower thereby buffering the effects of rapid temperature changes of the optics.\u003co:p\u003e\u003c\/o:p\u003e\u003c\/span\u003e\u003c\/p\u003e  \u003cp class=\"MsoNormal\" style=\"margin-bottom:0in;margin-bottom:.0001pt;line-height: 13.5pt;background:white\"\u003e\u003cspan style=\"font-family: Arial, sans-serif; color: rgb(34, 34, 34); background-image: initial; background-attachment: initial; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;\"\u003e\u003co:p\u003e \u003c\/o:p\u003e\u003c\/span\u003e\u003cspan style=\"color: rgb(34, 34, 34); font-family: Arial, sans-serif; line-height: 13.5pt;\"\u003eThe sealed, dry environment is impervious to internal fogging and contaminants such as fungus growing in between the lens elements. Our waterproof eyepiece is easier to clean, and there is no risk of cleaning solution migrating from the top of the lens and seeping around edges to be trapped in between elements. To insure a perfect seal we test every eyepiece in one meter of water for 30 minutes.\u003c\/span\u003e\u003c\/p\u003e\u003ctable class=\"data-table\" id=\"product-attribute-specs-table\" style=\"box-sizing: border-box; margin: 0px; padding: 0px; border-collapse: collapse; border-spacing: 0px; font-family: 'Open Sans', Arial, sans-serif; color: rgb(99, 99, 99); font-size: 14px; line-height: 21px; width: 700px; max-width: 50em; border: 1px solid silver; background-color: rgb(255, 255, 255);\"\u003e\u003ctbody style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003ctr class=\"first odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eSKU\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eES-EPWP6820-01\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eMANUFACTURER\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eExplore Scientific\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eOPTICAL DESIGN\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eWide Angle\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eBARREL SIZE\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eWARRANTY\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eLifetime Warranty\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eEYEPIECE FIELD OF VIEW - APPARENT\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e68º\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eEYEPIECE FOCAL LENGTH\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e20mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eEYEPIECE EYE RELIEF\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e15.3mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eEYEPIECE MANUFACTURER SERIES\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eExplore Scientific 68º Waterproof\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eEYEPIECE WEIGHT\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e8.7oz, 247g\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eFIELD STOP\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e22.8mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eNUMBER OF LENS ELEMENTS \u0026amp; GROUPS\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003e7 elements in 4 groups\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eSPECIAL FEATURE\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eWaterproof\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"even\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eCOMES WITH DUST CAPS?\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr class=\"last odd\" style=\"box-sizing: border-box; margin: 0px; padding: 0px;\"\u003e\n\u003cth class=\"label\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; font-weight: normal; vertical-align: top; text-transform: uppercase; font-family: Raleway, 'Helvetica Neue', Verdana, Arial, sans-serif; line-height: 1.4; white-space: nowrap; border-right-width: 1px; border-right-style: solid; border-right-color: silver; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; background: rgb(244, 244, 244);\"\u003eCOMES WITH EYE GUARD?\u003c\/th\u003e\n\u003ctd class=\"data last\" style=\"box-sizing: border-box; margin: 0px; padding: 10px; vertical-align: top; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: silver; font-family: Georgia, Times, 'Times New Roman', serif;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013288456303,"sku":"EPWP6820-01","price":151.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/20_1024x1024__94807.jpg?v=1766550524"},{"product_id":"28mm-68-deg-eyepiece","title":"Explore Scientific 68° Series 28mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 68° Series 28mm is a wide-field, argon-purged waterproof eyepiece in a 2-inch barrel, with a 31.8mm field stop and 21.6mm of eye relief. It measures 91.4mm long and 61.3mm across and weighs 16.1oz (458g), which is substantial in the hand and typical for a 2-inch eyepiece carrying this much field.\u003c\/p\u003e\n\u003cp\u003eThe 31.8mm field stop is the specification that matters most here, because it sets the true field independently of apparent field marketing. In a 1200mm telescope it works out to about 1.52°, and in an 826mm refractor about 2.2° — more than four full Moons across. Magnification is the telescope's focal length divided by 28, so 43x at 1200mm and 30x at 826mm.\u003c\/p\u003e\n\u003cp\u003eExplore Scientific builds the series from low-dispersion and high-refractive-index optical glasses with multilayer coatings, aimed at holding contrast and keeping the field flat out to the edge. The housing is sealed and argon-purged, and a soft silicone eyecup is fitted.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field deep-sky observers:\u003c\/strong\u003e a 1.5° true field at 1200mm takes in the whole of the Pleiades, the Double Cluster or the North America Nebula in one view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOwners of 2-inch focusers\u003c\/strong\u003e who want the wide true field a larger barrel makes physically possible, rather than the 1.25-inch ceiling of around 27mm of field stop.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 21.6mm of eye relief is generous by any standard, and comfortably enough to take in the full 68° field with spectacles on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven mount users:\u003c\/strong\u003e a wide apparent field buys drift time between nudges, which is time spent observing rather than repositioning.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone observing in damp air or heavy dew,\u003c\/strong\u003e where the argon-purged sealed housing does real work.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e68° apparent field of view:\u003c\/strong\u003e a step up in immersion from the 52° and 62° Series without the outer-field demands of an 82° or 100° design.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e31.8mm field stop:\u003c\/strong\u003e the figure that fixes true field. Multiply by 57.3 and divide by your telescope's focal length for the field in degrees.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e21.6mm eye relief:\u003c\/strong\u003e long enough to keep glasses on, and long enough that eye positioning stops being an effort during a long session.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2.00″ barrel:\u003c\/strong\u003e drops into any 2-inch focuser or diagonal, which is what allows a field stop this large.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow-dispersion and high-refractive-index optical glasses\u003c\/strong\u003e with multilayer coatings, specified by Explore Scientific for sharp contrast and a flat field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged sealed housing:\u003c\/strong\u003e waterproof, and resistant to the internal fogging that trapped humid air can produce as temperatures drop.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSoft silicone eyecup\u003c\/strong\u003e included.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished dimensions:\u003c\/strong\u003e 91.4mm long, 61.3mm wide, 16.1oz (458g).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty registration\u003c\/strong\u003e available through Explore Scientific.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eWide-field sweeping of large open clusters, nebulae and Milky Way star fields.\u003c\/li\u003e\n\u003cli\u003eFraming large objects that overflow a narrower eyepiece — the Veil, the Rosette, the Andromeda halo.\u003c\/li\u003e\n\u003cli\u003eLow-power finding before switching to a higher-magnification eyepiece.\u003c\/li\u003e\n\u003cli\u003eExtended observing sessions where 21.6mm of eye relief keeps things comfortable.\u003c\/li\u003e\n\u003cli\u003eObserving on an undriven Dobsonian, where apparent field translates into time on target.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRequires a 2-inch focuser or diagonal.\u003c\/strong\u003e The 2.00″ barrel does not step down to 1.25 inches, so a telescope with a 1.25-inch focuser only is outside its range. We are happy to check your focuser before you order.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 28. A 1200mm Dobsonian gives 43x; an 826mm refractor gives 30x; a 2000mm SCT gives 71x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 57.3 × 31.8 ÷ focal length. That is 1.52° at 1200mm and 2.2° at 826mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 28 divided by the telescope's focal ratio — 6mm at f\/4.7, 2.8mm at f\/10.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e 2-inch threaded filters are the match for a 2-inch eyepiece. Nebula filters at this focal length and field are one of the more rewarding combinations in visual astronomy.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e at 16.1oz this eyepiece shifts the balance of a small refractor or a Dobsonian noticeably. On a Dob, rebalancing with the tube tension or a counterweight sorts it out.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a 2-inch eyepiece only.\u003c\/strong\u003e A 2-inch focuser or a 2-inch diagonal is what it goes into. Send us your telescope model if you would like us to check that before it ships.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e16.1oz is a real weight to hang off a focuser.\u003c\/strong\u003e Light Dobsonians and short refractors will want rebalancing when it goes in, which a counterweight or a friction adjustment handles.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count, a group count or a filter thread specification\u003c\/strong\u003e for this eyepiece, so those rows are absent from the table below rather than estimated. If one of them decides the purchase for you, ask us and we will put the question to our Explore Scientific contact.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e68° is wide, not ultra-wide.\u003c\/strong\u003e The 82° and 100° Series go further if immersion is the goal; the 68° is the balance point between field width, eye relief and weight, and it is the lightest of the three at this sort of focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with an adapter, though the design target is the eye.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 2-inch focuser or diagonal and is ready immediately. Nothing to assemble or adjust. The only thing worth a moment is rebalancing a light telescope after 16.1oz goes on the back end.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 28. A 1000mm telescope gives 36x and a 1200mm gives 43x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much sky does it actually show?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e57.3 multiplied by the 31.8mm field stop, divided by your focal length. At 1200mm that is 1.52°, or about three full Moons side by side.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. 21.6mm of eye relief is among the more generous figures at this focal length, and it is enough to take in the whole 68° field with spectacles in place.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit a 1.25-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — the barrel is 2.00″. For a 1.25-inch focuser, the 52° Series 30mm covers similar low-power ground within the smaller barrel, and we stock it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with the 82° Series?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 82° gives a wider apparent field and a more immersive view; the 68° is lighter, easier on eye placement and easier on the outer field of a fast telescope. Tell us what you observe and on what telescope, and we will give you a straight recommendation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo nebula filters help at this focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eConsiderably, on emission nebulae. A 2-inch UHC or O-III threads into the barrel and darkens the background while passing the nebula's own light.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 458g, 2-inch, argon-purged 28mm eyepiece with a 68° apparent field, a 31.8mm field stop and 21.6mm of eye relief — wide, comfortable, low-power viewing built on low-dispersion and high-index glass. If you would like us to check that your focuser takes 2-inch eyepieces, or to suggest a nebula filter to pair with it, send us your telescope details and we will take it from there.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013289242735,"sku":"EPWP6828-01","price":235.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/2104280-2__00802.jpg?v=1766550530"},{"product_id":"34mm-68-deg-eyepiece","title":"Explore Scientific 68° Series 34mm Waterproof Eyepiece (2-Inch)","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 68° Series 34mm is a 2.00″ barrel wide-field eyepiece with a published eye relief of 26.4mm and a field stop diameter of 38.6mm. It measures 100.8mm long and 69.6mm wide and weighs 24.1oz; 685g. The optical design combines low dispersion and high refractive index glasses, and the housing is argon-purged and sealed against internal fogging and contamination.\u003c\/p\u003e\n\u003cp\u003eAt 34mm with a 38.6mm field stop, this is the widest true field in the 68° Series. True field is the field stop divided by the telescope's focal length, multiplied by 57.3: 2.24° in a 988mm refractor, 1.82° in a 1216mm apochromat, 1.47° in a 1500mm Maksutov. Magnification is focal length divided by 34 — 29x, 36x and 44x for those same telescopes.\u003c\/p\u003e\n\u003cp\u003eThe 68° apparent field sits between the flat, economical 52° Series and the immersive 82°. The practical effect is that at any given magnification the eye takes in noticeably more sky than a 52° eyepiece shows, without asking as much of the outer field as an 82° or 100° design does.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field deep-sky observers:\u003c\/strong\u003e 2.24° of true field in a 988mm refractor holds large open clusters, the North America Nebula and the Andromeda halo in one view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 26.4mm of eye relief is enough to see the entire 68° field with spectacles on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers building a matched set:\u003c\/strong\u003e the 34mm is parfocal with the rest of the 68° line, so swapping focal lengths does not mean refocusing from scratch.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilter users hunting faint nebulosity:\u003c\/strong\u003e low power, a large exit pupil and a wide true field is the combination narrowband filters were made for.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers in damp climates:\u003c\/strong\u003e argon purging and sealing keep the internal surfaces clear as the temperature falls.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e68° apparent field:\u003c\/strong\u003e a middle ground that gains substantially over a 52° design without the outer-field demands of an 82° or 100° eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e38.6mm field stop:\u003c\/strong\u003e the widest true field in the series, and the figure that determines how much sky you actually see.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e26.4mm eye relief:\u003c\/strong\u003e comfortable for extended sessions and practical with glasses on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow dispersion and high refractive index glasses in combination:\u003c\/strong\u003e low dispersion glass restrains colour error, high index glass lets the designer bend light with gentler curves, and gentler curves make the outer field easier to correct.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged and sealed:\u003c\/strong\u003e an inert fill does not carry the moisture that trapped air does, so internal fogging and contamination are designed out rather than managed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2.00″ barrel:\u003c\/strong\u003e fits any 2-inch focuser or diagonal directly.\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eRemovable, foldable soft silicone rubber eyecup.\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eParfocal with the rest of the 68° line,\u003c\/strong\u003e which keeps focus changes to a nudge when switching eyepieces.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished dimensions:\u003c\/strong\u003e 100.8mm long, 69.6mm wide, 24.1oz; 685g.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLow-power deep-sky sweeping through the summer and winter Milky Way.\u003c\/li\u003e\n\u003cli\u003eLarge emission nebulae with a 2-inch narrowband filter in place.\u003c\/li\u003e\n\u003cli\u003eFraming extended objects — the Pleiades, the Hyades, the Double Cluster, the Veil.\u003c\/li\u003e\n\u003cli\u003eComet observing, where the whole coma and a length of tail can share the field.\u003c\/li\u003e\n\u003cli\u003eAcquiring and centring targets before switching to a higher-power eyepiece in the same parfocal set.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocuser:\u003c\/strong\u003e the 2.00″ barrel fits 2-inch focusers and diagonals directly. There is no 1.25-inch path for it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 34. A 750mm Newtonian gives 22x; a 1216mm apochromat 36x; a 2000mm SCT 59x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 38.6 ÷ focal length × 57.3. A 750mm Newtonian yields 2.95°; a 2000mm SCT 1.11°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 34 ÷ focal ratio. An f\/5 Newtonian gives 6.8mm, an f\/6.5 refractor 5.23mm, an f\/8 apochromat 4.25mm and an f\/10 SCT 3.4mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight and size:\u003c\/strong\u003e 24.1oz; 685g in a 69.6mm-wide body. That is a substantial eyepiece, and on a small refractor or a Dobsonian it can shift the balance point enough to want a counterweight or a friction adjustment.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the series:\u003c\/strong\u003e parfocal with the other 68° focal lengths, so a set built around it keeps a consistent eye position and focus plane.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e Explore Scientific does not publish a filter thread specification for this eyepiece, so that row is absent from the table below rather than estimated.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis is a large, heavy eyepiece.\u003c\/strong\u003e 100.8mm long, 69.6mm wide and 24.1oz; 685g means a well-supported focuser is worth having, and a small tube may need rebalancing when it goes in. A magnetic counterweight solves that on a Dobsonian and costs very little.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 69.6mm body diameter is worth measuring against your eyepiece case.\u003c\/strong\u003e Standard 2-inch eyepiece slots in some cases are cut narrower than that.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt needs a 2-inch focuser or diagonal.\u003c\/strong\u003e Telescopes with 1.25-inch focusers cannot take a 2.00″ barrel, and the 1.25-inch focal lengths in the 68° Series are the ones to look at instead — we stock those and can suggest the closest equivalent field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAt f\/5 the exit pupil is 6.8mm.\u003c\/strong\u003e That is close to the limit of a well dark-adapted eye and beyond it for many older eyes, so some of the light gathered will fall outside the iris. Between f\/6 and f\/10 the eyepiece works comfortably.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count, a coating designation or a filter thread for this eyepiece,\u003c\/strong\u003e so those rows are absent below rather than estimated. If one of them decides the purchase for you, ask us and we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 2-inch focuser or diagonal and is ready immediately. There is nothing to assemble or align. The one thing worth doing on a light tube is rebalancing after fitting it, since it weighs 24.1oz; 685g.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification and true field will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eMagnification is your telescope's focal length divided by 34. True field is 38.6 divided by that focal length, multiplied by 57.3. A 1000mm telescope gives 29x and 2.21°.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. 26.4mm of eye relief covers the full 68° field for most spectacle wearers, and the silicone eyecup folds down.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare to the 82° Series?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 82° shows a wider apparent field and a more immersive view; the 68° puts its budget into eye relief and a gentler outer field, and at 34mm it also delivers a very large true field. Tell us what you observe most and we will give you a straight comparison.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it parfocal with my other 68° eyepieces?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes — Explore Scientific specifies the 68° line as parfocal, so changing focal lengths within the series needs only a small focus correction.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it work on a fast Newtonian?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt will, though at f\/5 the 34mm produces a 6.8mm exit pupil, which is at the edge of what a dark-adapted eye uses. Shorter focal lengths in the series suit fast optics better, and we can suggest one that keeps a similar apparent field.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 34mm, 2-inch, argon-purged eyepiece with a 68° apparent field, 26.4mm of eye relief and a 38.6mm field stop — the widest true field in the series, parfocal with the rest of the line, and comfortable with glasses on. If you would like the magnification, true field and exit pupil worked out for the telescope you own, send us its aperture and focal length and we will do it with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013290324079,"sku":"EPWP6834-01","price":304.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/34_1024x1024__72695.jpg?v=1766550536"},{"product_id":"40mm-68-deg-eyepiece","title":"Explore Scientific 68° Series 40mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 68° Series 40mm is the long focal length end of the 68° range: a 2-inch, argon-purged waterproof eyepiece with a 45.5mm field stop and 31mm of eye relief. Explore Scientific publishes it as 114.2mm long, 80.3mm across and 35.2 oz (998 g).\u003c\/p\u003e\n\u003cp\u003eThe 45.5mm field stop is the number that matters most here, because it sets the true field directly. Divide it by your telescope's focal length and multiply by 57.3 and you have the field in degrees: 5.4° in a 480mm refractor, 2.6° in a 988mm, 2.2° in a 1200mm SCT. That is close to the largest true field a 2-inch barrel can physically pass, which is what a 40mm eyepiece in this format is for.\u003c\/p\u003e\n\u003cp\u003eMagnification stays low by design — 12x in a 480mm telescope, 25x in a 1000mm — and the optical design uses low-dispersion glass with multilayer coatings, aimed at holding contrast and flatness right out to the edge of a wide field.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field sweepers:\u003c\/strong\u003e a 5.4° field in a short refractor covers the Hyades, the Pleiades with room around them, and long stretches of the Milky Way in one view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers hunting large, faint objects:\u003c\/strong\u003e the North America Nebula, the Veil and the larger open clusters are objects that need field before they need magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 31mm of eye relief is generous by any measure and makes observing with glasses on genuinely comfortable rather than merely possible.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone who finds targets by star-hopping:\u003c\/strong\u003e a low-power, wide-field eyepiece is the one you locate with before switching to something shorter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who want a matched set:\u003c\/strong\u003e the 68° Series is parfocal, so this sits at the long end of a range that behaves consistently.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e40mm focal length in a 2-inch barrel:\u003c\/strong\u003e the format that makes a wide true field possible in the first place.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e45.5mm field stop:\u003c\/strong\u003e the published figure that sets true field. Divide it by your focal length and multiply by 57.3 for degrees.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e68° apparent field of view,\u003c\/strong\u003e wider than the 52° and 62° Series while staying easier on the outer field than an 82° design.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e31mm eye relief:\u003c\/strong\u003e among the most generous figures Explore Scientific publishes across their eyepiece range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow-dispersion glass with multilayer coatings,\u003c\/strong\u003e aimed at high contrast, high resolution and a flat field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon purged and waterproof,\u003c\/strong\u003e so internal fogging is not part of a long, damp session.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemovable, foldable silicone rubber eyecup,\u003c\/strong\u003e which folds down for spectacle wearers and back up for observing without.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished dimensions:\u003c\/strong\u003e 114.2mm long, 80.3mm wide, 35.2 oz (998 g).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eParfocal across the 68° Series,\u003c\/strong\u003e so swapping focal lengths in the dark needs only a small focus correction.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLow-power sweeping of the Milky Way and large open clusters.\u003c\/li\u003e\n\u003cli\u003eLarge emission and reflection nebulae, particularly with a narrowband filter fitted.\u003c\/li\u003e\n\u003cli\u003eFinding and framing targets before switching to a higher power.\u003c\/li\u003e\n\u003cli\u003eComet observing, where a wide field and a bright image suit a diffuse tail.\u003c\/li\u003e\n\u003cli\u003eObserving with glasses on, where 31mm of eye relief removes the usual compromise.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRequires a 2-inch focuser or diagonal.\u003c\/strong\u003e The 45.5mm field stop is why — a 1.25-inch barrel physically cannot pass a field this wide, so there is no 1.25-inch version of this combination.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length divided by 40. A 1200mm SCT gives 30x, a 750mm Newtonian gives 19x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 45.5 divided by focal length, times 57.3. A 1000mm telescope gives 2.6°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 40 divided by your focal ratio. In an f\/10 that is 4mm; in an f\/6 it is 6.7mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e takes standard 2-inch threaded filters. A wide-field eyepiece and a narrowband or oxygen-III filter is a well-matched pairing for large nebulae, and we stock both.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e at 998 g this is a heavy eyepiece. On a small refractor or a Dobsonian it will shift the balance point, which a counterweight or a moved tube ring sorts out easily.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil sets a practical limit at fast focal ratios.\u003c\/strong\u003e In an f\/6 telescope a 40mm eyepiece produces a 6.7mm exit pupil, which is wider than most adult eyes dilate — some of that light falls outside your pupil, and in an obstructed telescope the secondary shadow can become visible. In an f\/8 or slower instrument the figures land comfortably, and if you are unsure where your telescope falls we can work it out with you before you order.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt weighs 998 g.\u003c\/strong\u003e A 2-inch focuser handles that without complaint, though a lightweight tube may want rebalancing when it goes in. That is a one-time adjustment.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is 114.2mm long and 80.3mm wide,\u003c\/strong\u003e so it takes a full-size slot in an eyepiece case rather than a standard one. Worth accounting for if your case is already full — we can suggest a case sized for 2-inch eyepieces.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow power is the point.\u003c\/strong\u003e A 40mm eyepiece is not the one for planetary detail; it is the one that frames the object and finds it. It works best alongside shorter focal lengths in the same series.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Projection imaging is possible with an adapter, though the design is aimed at the eye.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 2-inch focuser or diagonal and is ready immediately. The only thing worth doing on the first night is rechecking the telescope's balance, since 998 g at the back end is noticeable on a light tube.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification and field will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eFocal length divided by 40 for magnification, and 45.5 divided by focal length times 57.3 for true field in degrees. A 1000mm telescope gives 25x over 2.6°.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit a 1.25-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — the barrel is 2 inches, and the 45.5mm field stop is wider than a 1.25-inch barrel can pass. A telescope with a 2-inch focuser or a 2-inch diagonal is what this eyepiece is built for.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. 31mm of eye relief is generous, and the silicone eyecup folds down so your glasses sit at the right distance from the lens.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it take filters?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, standard 2-inch threaded filters, which thread into the base of the barrel. Wide-field observing and a narrowband filter go together well on large nebulae.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with the 82° Series?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 82° designs show a wider apparent field; this one is built around a very large field stop, 31mm of eye relief and low power. At 40mm the 68° format is what puts the maximum true field through a 2-inch barrel, which is a different goal from maximum immersion.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 40mm 2-inch argon-purged eyepiece with a 45.5mm field stop, a 68° apparent field and 31mm of eye relief — about as much true field as a 2-inch barrel will pass, with room for glasses. If you would like us to work out the field and exit pupil it will give in your particular telescope, send us the aperture and focal length and we will run the numbers.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013290979439,"sku":"EPWP6840-01","price":429.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/40mm__83807.jpg?v=1766550542"},{"product_id":"12mm-92-eyepiece-2","title":"Explore Scientific 92° Series 12mm Long Eye Relief 2-Inch Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 92° Series 12mm is a hyper-wide-field eyepiece in a 2-inch waterproof barrel, published with a 92° apparent field of view, 20.02mm of eye relief and a 27.46mm field stop. It measures 152mm long by 70mm wide and weighs 2.4 lbs.\u003c\/p\u003e\n\u003cp\u003eThe combination that makes this eyepiece unusual is 92 degrees of apparent field with more than 20mm of eye relief at a 12mm focal length. Those two properties normally pull against each other — wide apparent fields tend to force the eye close to the lens, and short focal lengths make it worse. Holding 20.02mm here is what the \"Long Eye Relief\" in the name refers to, and it is what allows the whole 92° field to be taken in comfortably, including with eyeglasses on.\u003c\/p\u003e\n\u003cp\u003eAt 12mm the magnification lands in the productive middle-high range: 79x in a 952mm refractor, 100x in a 1200mm SCT, 125x in a 1500mm Dobsonian. Combined with a 92° apparent field, the true field at those powers is far larger than a conventional eyepiece would give — which is the practical reason people buy hyper-wide designs.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers\u003c\/strong\u003e who want high enough magnification to darken the sky background while keeping an object and its surroundings in the same view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven mount owners:\u003c\/strong\u003e at 92° apparent field an object takes roughly twice as long to cross the field as it would in a 50° eyepiece at the same power, which changes how a session feels.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers\u003c\/strong\u003e who have found most wide-field eyepieces impossible to use with spectacles — 20.02mm of eye relief is what makes it work here.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers using averted vision:\u003c\/strong\u003e a wide field gives the eye room to look slightly off-target, which is how faint detail is picked up.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOwners of 2-inch focusers and diagonals\u003c\/strong\u003e who want to use the full aperture of the format.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers in damp conditions,\u003c\/strong\u003e where the waterproof housing does its work.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e92° apparent field of view:\u003c\/strong\u003e a hyper-wide class field that fills more of the visual field than the eye can take in at a single glance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e20.02mm of eye relief at 12mm focal length:\u003c\/strong\u003e the defining specification, and what makes the field usable with glasses on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e27.46mm field stop:\u003c\/strong\u003e the figure that sets true field — divide by the telescope's focal length and multiply by 57.3 for degrees.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2.00″ barrel:\u003c\/strong\u003e requires a 2-inch focuser or diagonal, which is what allows the field stop to exceed the 1.25-inch limit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof construction\u003c\/strong\u003e in line with the sealed Explore Scientific waterproof eyepiece range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e152mm long, 70mm wide, 2.4 lbs:\u003c\/strong\u003e a physically large eyepiece, which is inherent to holding this field and this eye relief together.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMedium-to-high power deep-sky observing where a dark sky background and a wide surround are both wanted.\u003c\/li\u003e\n\u003cli\u003eGlobular clusters, planetary nebulae, galaxy groups and the brighter emission nebulae.\u003c\/li\u003e\n\u003cli\u003eExtended lunar observing, where the wide field keeps the whole disc and its surroundings in view at 12mm in a short telescope.\u003c\/li\u003e\n\u003cli\u003eUndriven Dobsonian work, where field width buys time between nudges.\u003c\/li\u003e\n\u003cli\u003eObserving with eyeglasses on, which most hyper-wide eyepieces make difficult.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRequires a 2-inch focuser or diagonal.\u003c\/strong\u003e The 2.00″ barrel does not fit a 1.25-inch fitting, and no adapter converts downward, because the field stop is larger than a 1.25-inch barrel can pass.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 12. A 714mm refractor gives 60x; a 1200mm SCT gives 100x; a 1900mm Maksutov gives 158x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 27.46mm ÷ telescope focal length × 57.3. In a 1200mm telescope that works out to about 1.3°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e at 2.4 lbs this eyepiece shifts the balance of most telescopes noticeably. On a Dobsonian a counterweight at the rear of the tube settles it; on an equatorial mount it is a matter of rebalancing after fitting. We stock counterweights for both.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocuser capacity:\u003c\/strong\u003e a 2.4 lb eyepiece hanging off a focuser drawtube is real load. A rack-and-pinion or a well-tensioned Crayford handles it; a lightly built focuser may need its tension adjusting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e Explore Scientific does not publish the filter thread specification for this eyepiece, so we are not quoting one. If a 2-inch narrowband filter is part of your plan, ask and we will confirm the thread with our rep first.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis is a 2-inch eyepiece and it needs a 2-inch focuser or diagonal.\u003c\/strong\u003e A 27.46mm field stop is physically larger than a 1.25-inch barrel can pass, so stepping down is not possible. If your telescope has a 1.25-inch focuser, the 62° and 72° Series cover similar ground in that format, and we stock them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAt 2.4 lbs it is heavy enough to change the balance of the telescope.\u003c\/strong\u003e Rebalancing after fitting takes a moment, and a magnetic or clamp-on counterweight solves it permanently on a Dobsonian.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA 92° field is larger than the eye takes in at once.\u003c\/strong\u003e Observers typically scan around the field rather than seeing it all at a glance, which is the intended experience of a hyper-wide design rather than a shortcoming.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish the element count, coating specification or filter thread\u003c\/strong\u003e for this model, so those rows read \"Not published by vendor\" below rather than carrying an estimate. If one of those figures matters, ask and we will get it from our rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a physically large eyepiece at 152mm by 70mm,\u003c\/strong\u003e which is worth allowing for in a case designed around conventional oculars. We can suggest a case that fits it if yours is already full.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 2-inch focuser or diagonal and is ready to use. The one thing worth doing afterwards is rebalancing the telescope, since at 2.4 lbs it is heavy enough to shift the centre of gravity.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 12. A 1200mm telescope gives 100x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit a 1.25-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — the barrel is 2 inches and the 27.46mm field stop is wider than a 1.25-inch barrel can pass. For a 1.25-inch focuser, the 62° and 72° ED Series are the wide-field options, and we carry both.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes — that is the point of the 20.02mm of eye relief. Very few eyepieces combine a 92° field with enough eye relief to take the whole field in through spectacles.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much sky does it show?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eTake the 27.46mm field stop, divide by your telescope's focal length and multiply by 57.3. In a 1500mm Dobsonian that is about 1.05° at 125x, which is a lot of sky for that magnification.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare to the 82° Series?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eA wider apparent field at 92° against 82°, and this model is specified around long eye relief. It is also larger and heavier. Which one suits depends on your focuser, your mount and whether you observe with glasses — tell us your setup and we will help you choose.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it good on an undriven telescope?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eParticularly so. The wide apparent field is what keeps an object in view between nudges at a magnification that would otherwise need constant attention.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 12mm eyepiece with a 92° apparent field, 20.02mm of eye relief and a 27.46mm field stop in a 2-inch waterproof barrel — hyper-wide field at a working magnification, with enough eye relief to use it through glasses. If you would like us to confirm it suits your focuser and check whether a counterweight would help your balance, send us your telescope model and we will work it out with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013359464559,"sku":"EPWP9212-01","price":429.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/12mm_25252092_2525202__28314.1693593625.1280.1280.jpg?v=1766551051"},{"product_id":"17mm-92-eyepiece-2","title":"Explore Scientific 17MM 92 deg EYEPIECE - 2\"","description":"\u003ccenter style=\"box-sizing: border-box; margin: 0px; padding: 0px; font-family: \" open sans arial sans-serif rgb font-size:=\"\" background-color:=\"\"\u003e\n\u003ch1 style=\"box-sizing: border-box; margin: 0px 0px 0.7em; padding: 0px; font-size: 16px; font-weight: 400; font-family: Raleway, \" helvetica neue verdana arial sans-serif font-style: normal line-height: text-rendering: optimizelegibility text-transform: uppercase\u003eEXPLORE SCIENTIFIC 17MM 92° 2\" LONG EYE RELIEF ARGON PURGED\u003c\/h1\u003e\n\u003ch1 style=\"box-sizing: border-box; margin: 0px 0px 0.7em; padding: 0px; font-size: 16px; font-weight: 400; font-family: Raleway, \" helvetica neue verdana arial sans-serif line-height: text-rendering: optimizelegibility text-transform: uppercase\u003e\n\u003ccenter style=\"box-sizing: border-box; margin: 0px; padding: 0px; font-family: \" open sans arial sans-serif font-size: text-transform: none\u003e\u003c\/center\u003e\n\u003cspan style=\"font-family: \" open sans arial sans-serif font-size: text-align: start text-transform: none\u003eWhat this is, is a beautiful example of a wide field of view eyepiece with a luxuriously comfortable long eye relief- these two features combining for a truly immersive viewing experience when it comes to the majesty of the night skies- the comfort of the eye piece letting you forget that it's there- and the near maximum hyper-wide field of view almost letting you forget there's anything between you and the beautiful tapestry of the night sky and all it's stars. It's certainly a high quality eyepiece then, with it's broad field of view and extended eye relief ensuring that mix of comfort and practicality that can be called optimal. It's an ideal eyepiece to practice averted viewing with, as well; the wide field of view letting you look slightly to the side of faint items to see them better by allowing more sensitive parts of your eye to be what's focused towards them. And that's not all the broad field of view is good for! It also makes it easier to find objects in the night sky and keep them in your field of view for far longer without adjustment than eyepieces with lower FOV's can manage. All in all, it's a high quality example of a comfortable eyepiece- and certainly worth the investment to any interested in experiencing a wide field of view as they gaze upon the night sky in all it's beauty and majesty. \u003c\/span\u003e\u003cbr style=\"box-sizing: border-box; margin: 0px; padding: 0px; font-family: \" open sans arial sans-serif font-size: text-align: start text-transform: none\u003e\u003cbr style=\"box-sizing: border-box; margin: 0px; padding: 0px; font-family: \" open sans arial sans-serif font-size: text-align: start text-transform: none\u003e\n\u003c\/h1\u003e\n\u003ch1 style=\"box-sizing: border-box; margin: 0px 0px 0.7em; padding: 0px; font-size: 16px; font-weight: 400; font-family: Raleway, \" helvetica neue verdana arial sans-serif line-height: text-rendering: optimizelegibility text-transform: uppercase\u003eEXPLORE SCIENTIFIC 17MM 92° 2\" LONG EYE RELIEF ARGON PURGED FEATURES!\u003c\/h1\u003e\n\u003ch1 style=\"box-sizing: border-box; margin: 0px 0px 0.7em; padding: 0px; font-size: 16px; font-weight: 400; font-family: Raleway, \" helvetica neue verdana arial sans-serif line-height: text-rendering: optimizelegibility text-transform: uppercase\u003e\n\u003ccenter style=\"box-sizing: border-box; margin: 0px; padding: 0px; font-family: \" open sans arial sans-serif font-size: text-transform: none\u003e\u003c\/center\u003e\n\u003cbr style=\"box-sizing: border-box; margin: 0px; padding: 0px; font-family: \" open sans arial sans-serif font-size: text-align: start text-transform: none\u003e\u003cbr style=\"box-sizing: border-box; margin: 0px; padding: 0px; font-family: \" open sans arial sans-serif font-size: text-align: start text-transform: none\u003e\u003cul style=\"box-sizing: border-box; margin: 0px 0px 1.5em; padding: 0px; list-style-position: outside; list-style-image: initial; font-family: \" open sans arial sans-serif font-size: text-align: start text-transform: none\u003e\n\u003cli style=\"box-sizing: border-box; margin: 0px 0px 0px 2em; padding: 0px;\"\u003eWaterproofed\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin: 0px 0px 0px 2em; padding: 0px;\"\u003e92° Apparent Field of View\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin: 0px 0px 0px 2em; padding: 0px;\"\u003e2\" Barrel\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin: 0px 0px 0px 2em; padding: 0px;\"\u003e20mm Eye Relief\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin: 0px 0px 0px 2em; padding: 0px;\"\u003eFilter Threads: Standard 2\" Filter Thread (M48 x 0.75)\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin: 0px 0px 0px 2em; padding: 0px;\"\u003eBlackened Lens Edges: Yes\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin: 0px 0px 0px 2em; padding: 0px;\"\u003eBarrel Safety Recess: Tapered Barrel\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin: 0px 0px 0px 2em; padding: 0px;\"\u003eBarrel Type: Tapered Barrel\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin: 0px 0px 0px 2em; padding: 0px;\"\u003eEnd Caps: 2\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin: 0px 0px 0px 2em; padding: 0px;\"\u003eRubber Eye Guard: Rubber Folding Type\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/h1\u003e\n\u003c\/center\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013359759471,"sku":"EPWP9217-01","price":512.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/17mm_25252092_2525202__78293.1693593626.1280.1280.jpg?v=1766551059"},{"product_id":"explore-scientific-62deg-5-5mm-waterproof-eyepiece","title":"Explore Scientific 62° Series 5.5mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 62° Series 5.5mm is a short focal length, argon-purged waterproof eyepiece on a 1.25-inch barrel. Explore Scientific publishes 12.9mm of eye relief for it, and gives the body as 57.5mm long and 38mm across — a compact eyepiece that does not unbalance a small refractor or a lightweight alt-azimuth head.\u003c\/p\u003e\n\u003cp\u003eAt 5.5mm this is the high-power end of a focal-length set. In a 480mm f\/6 refractor it gives 87x, in a 1000mm telescope 182x, and in a 1400mm Maksutov 255x. The 62° apparent field sits between the flat, conservative 52° designs and the wide 68° and 82° series — enough width that a planet at high power stays in view for a workable stretch on an undriven mount, without asking as much of the outer field as a 100° design does.\u003c\/p\u003e\n\u003cp\u003eThe series is described by Explore Scientific as near-parfocal, so moving between focal lengths within the 62° range takes only a small focus correction rather than a full refocus.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary observers:\u003c\/strong\u003e 5.5mm lands in the range where the Jovian belts, the Cassini division and the Martian polar cap become the subject rather than a hint.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar observers\u003c\/strong\u003e working at high power along the terminator, where the contrast between lit and shadowed terrain is at its strongest.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble-star observers:\u003c\/strong\u003e high magnification widens the apparent separation of a close pair, and a 62° field keeps the pair on view between looks.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShort-focus telescope owners:\u003c\/strong\u003e in a fast refractor a 5.5mm is the eyepiece that finally reaches planetary magnification — 87x in a 480mm f\/6, 136x in a 750mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers in damp conditions:\u003c\/strong\u003e the argon-purged, sealed housing is built for dew, humidity and night-long temperature swings.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e5.5mm focal length:\u003c\/strong\u003e a high-power eyepiece in almost any telescope it is used in.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e62° apparent field of view:\u003c\/strong\u003e wider than a Plössl, narrower and easier on the outer field than the 82° and 100° designs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e12.9mm eye relief,\u003c\/strong\u003e which at a 5.5mm focal length is more than a simple design of the same power would give — short eyepieces are where eye relief is normally sacrificed first.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged, waterproof housing:\u003c\/strong\u003e dry inert gas inside the sealed body will not condense on internal surfaces the way trapped humid air does.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25-inch barrel:\u003c\/strong\u003e drops into any 1.25-inch focuser or diagonal without an adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e57.5mm long and 38mm wide:\u003c\/strong\u003e small and light enough that it changes nothing about how a telescope balances.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNear-parfocal across the 62° Series,\u003c\/strong\u003e so a set behaves consistently when you swap between focal lengths in the dark.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlat-field multi-element design\u003c\/strong\u003e aimed at contrast, which is what supports averted vision on faint targets.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHigh-power lunar and planetary observing.\u003c\/li\u003e\n\u003cli\u003eSplitting close double stars.\u003c\/li\u003e\n\u003cli\u003eSmall, bright deep-sky targets — planetary nebulae, globular cluster cores, compact galaxies.\u003c\/li\u003e\n\u003cli\u003eObserving from a light-polluted site, where high magnification darkens the sky background against the object.\u003c\/li\u003e\n\u003cli\u003eFilling the short end of a matched 62° Series set.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal\u003c\/strong\u003e directly. In a 2-inch focuser it goes in with a 2-inch to 1.25-inch adapter, which we stock.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length divided by 5.5. A 900mm Newtonian gives 164x; a 1400mm Maksutov gives 255x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 5.5 divided by your telescope's focal ratio. In an f\/6 that is 0.92mm, in an f\/10 0.55mm — small pupils, which is normal at this magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e standard 1.25-inch threaded filters are the usual pairing — a lunar or neutral-density filter for the Moon, colour filters for planetary detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 5.5mm is already at the high-power end, so adding a 2x or 3x extender pushes past what most apertures can use. Longer focal lengths in the series pair better with an extender, and we can suggest a combination that keeps you inside your telescope's useful range.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish a field stop diameter or a weight for this eyepiece.\u003c\/strong\u003e Those rows read as unpublished below rather than being estimated. The true field can still be worked out closely from the 62° apparent field divided by your magnification, and if you need the field stop figure itself we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAtmospheric seeing governs a 5.5mm eyepiece.\u003c\/strong\u003e On a steady night it shows what your aperture can resolve; on a turbulent night a longer focal length will show more detail. That is the air rather than the optics, and it is why a 5.5mm belongs in a set rather than on its own.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e12.9mm of eye relief is workable but not generous.\u003c\/strong\u003e Observing with glasses on is possible for some prescriptions and tight for others; the 68° Series 40mm and other long-eye-relief designs carry considerably more if that is the deciding factor, and we are happy to compare them for you.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe exit pupil is small at this focal length,\u003c\/strong\u003e so floaters in your own eye can become visible. That is a normal effect of high magnification in any eyepiece rather than anything happening in the glass.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with the right adapter, and we can supply one, though the design target here is the eye.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops straight into any 1.25-inch focuser or diagonal and is ready to use. There is nothing to assemble, collimate or adjust, and no maintenance between sessions beyond keeping the caps on.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 5.5. A 1000mm telescope gives 182x, a 1200mm gives 218x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs 5.5mm too much magnification for my telescope?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt depends on aperture and on the night. A rough practical ceiling is about twice the aperture in millimetres, so a 100mm telescope tops out near 200x — 5.5mm sits comfortably inside that at 1400mm focal length and beyond it in a very long-focus instrument. Tell us your aperture and focal length and we will work out where it lands.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use filters with it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. Standard 1.25-inch threaded filters thread into the base of the barrel — lunar, neutral density, colour and narrowband.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does argon purging actually do?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe sealed body is filled with dry argon instead of ordinary air. With no moisture inside, the internal surfaces have nothing to fog with when the temperature drops through the night.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does the 62° field compare to a Plössl?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eA Plössl typically shows about 50 degrees. The extra 12 degrees here reads as a noticeably larger window, and it buys drift time at high power on an undriven mount, which is where it matters most.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 5.5mm argon-purged waterproof eyepiece with a 62° apparent field, 12.9mm of eye relief and a 1.25-inch barrel, in a compact 57.5mm body — the high-power end of a near-parfocal series built around contrast. If you would like help working out which focal lengths would round out your set for the telescope you own, send us its aperture and focal length and we will map it out with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013376667759,"sku":"EPWP6255LE-01","price":67.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/62Degree_55_1__09707.jpg?v=1766552212"},{"product_id":"explore-scientific-62deg-9mm-waterproof-eyepiece","title":"Explore Scientific 62° Series 9mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 62° Series 9mm is an argon-purged waterproof eyepiece with a 1.25-inch barrel, 12.6mm of eye relief and a published body size of 57mm long by 38mm wide. At 9mm it sits toward the high-power end of a general-purpose focal-length set: 79x in a 714mm refractor, 111x in a 1000mm telescope, 133x in a 1200mm Schmidt-Cassegrain.\u003c\/p\u003e\n\u003cp\u003eExplore Scientific specifies the 62° Series as a flat-field, multi-element design with contrast good enough to support averted vision on faint targets, and describes the series as near-parfocal — swapping between focal lengths in the range asks for little more than a touch on the focuser rather than a full refocus.\u003c\/p\u003e\n\u003cp\u003e62 degrees is a comfortable apparent field. It is wider than a Plössl's 50 degrees by enough to notice, without pushing the eye position or the outer-field demands that 82° and 100° designs bring.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar and planetary observers:\u003c\/strong\u003e 9mm is the focal length that turns most telescopes into planetary instruments, and the flat field keeps detail crisp when the object drifts off centre.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble-star observers:\u003c\/strong\u003e enough magnification to open moderately close pairs, with 12.6mm of eye relief so the eye can hold position through a careful look.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers building a matched set:\u003c\/strong\u003e the near-parfocal design across the 62° Series means changing power costs a small focus tweak rather than a hunt.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers working in dew and damp air:\u003c\/strong\u003e the argon-purged, sealed body is built for conditions that fog a conventional eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUsers of compact telescopes:\u003c\/strong\u003e a 57mm x 38mm body is small and light enough that it will not upset the balance of a short tube or a small alt-azimuth head.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e9mm focal length:\u003c\/strong\u003e the workhorse high-power step in most eyepiece sets, sitting between medium-power scanning and the very short focal lengths that only good seeing supports.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e62° apparent field of view:\u003c\/strong\u003e a step up in immersion from a Plössl, and an easier outer field than the wide-angle series.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged and sealed:\u003c\/strong\u003e the inert fill displaces the moisture-bearing air that condenses inside an unsealed eyepiece when temperatures drop.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlat-field multi-element design\u003c\/strong\u003e specified by Explore Scientific, aimed at sharpness that holds from the centre of the field outward.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e12.6mm eye relief:\u003c\/strong\u003e published for this focal length, which is generous compared with a 9mm Plössl where eye relief scales down with focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNear-parfocal within the series,\u003c\/strong\u003e so a change of magnification is close to a straight swap.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25-inch barrel\u003c\/strong\u003e with a standard filter thread.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e57mm long, 38mm wide:\u003c\/strong\u003e the published body dimensions.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHigh-power lunar work along the terminator, where craterlets and rilles reward magnification.\u003c\/li\u003e\n\u003cli\u003ePlanetary detail — Jovian belt structure, Saturn's ring division, Martian albedo features at opposition.\u003c\/li\u003e\n\u003cli\u003eSplitting double stars of moderate separation.\u003c\/li\u003e\n\u003cli\u003eCompact deep-sky targets: planetary nebulae, globular cluster cores, small bright galaxies.\u003c\/li\u003e\n\u003cli\u003eDamp-site and coastal observing where a sealed housing keeps the session going.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal\u003c\/strong\u003e directly. A 2-inch focuser takes it with a 2-inch to 1.25-inch adapter, which most 2-inch diagonals already include.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 9. A 500mm reflector gives 56x, a 714mm refractor 79x, a 1200mm SCT 133x, a 2000mm SCT 222x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e Explore Scientific does not publish a field stop diameter for this eyepiece, so the true field is approximated as 62° divided by the magnification — about 0.56° at 111x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e the barrel takes standard 1.25-inch threaded filters. A lunar or neutral-density filter pairs naturally with 9mm on a bright Moon.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 2x extender turns this into an effective 4.5mm, which in a long-focus telescope reaches magnifications that only steady nights support.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the series:\u003c\/strong\u003e the near-parfocal design means a 9mm and a longer 62° eyepiece can be exchanged mid-session with minimal refocusing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish a weight, element count or field stop diameter\u003c\/strong\u003e for this eyepiece — the weight cell on their own spec table is blank. Those rows read as not published below rather than carrying an estimate. If one of them decides the purchase, ask us and we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e12.6mm of eye relief is workable rather than generous.\u003c\/strong\u003e Most observers find it comfortable with the eyecup up; for observing with glasses on, the 72° ED Series carries more eye relief and we stock it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAt 9mm the exit pupil is small.\u003c\/strong\u003e In an f\/10 telescope it is 0.9mm, which is where floaters in your own eye can start to become visible — a normal effect of high magnification rather than anything happening in the optics.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 62° field is moderate by design.\u003c\/strong\u003e If a broad, immersive view is what you are after, the 82° and 100° Series cover that ground; the 62° Series is built around flat-field sharpness and value.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproofing covers immersion, not use underwater.\u003c\/strong\u003e The sealed, argon-filled housing is there so heavy dew, rain and a drop into wet grass are non-events.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 1.25-inch focuser or diagonal and is ready to observe with. There is nothing to assemble, align or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 9. A 1000mm telescope gives 111x; a 1500mm Maksutov gives 167x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does argon purging change?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eArgon is inert and carries no moisture, so once the housing is sealed with it there is nothing inside to condense on the internal lens surfaces when the eyepiece cools. Sealed air would fog.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use filters with it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. Standard 1.25-inch threaded filters screw into the bottom of the barrel — lunar, neutral density, colour and narrowband alike.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with a 9mm Plössl?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eA wider apparent field at 62° against roughly 50°, a flat-field multi-element design, more eye relief than a 9mm Plössl typically offers, and a sealed argon-purged body. The differences show most at the field edge and in damp conditions.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it work in my Dobsonian?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, in any 1.25-inch focuser. On an undriven mount 9mm produces enough magnification that objects cross the field fairly quickly, so the 62° field is doing useful work buying drift time.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a sealed, argon-purged 9mm eyepiece with a flat 62° field, 12.6mm of eye relief and a 1.25-inch filter-threaded barrel, in a compact 57 x 38mm body — a high-power focal length that stays comfortable and holds sharpness across the field. If you would like help working out which focal lengths would round out your set, send us your telescope's aperture and focal length and we will map it out with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013376700527,"sku":"EPWP6209LE-01","price":67.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP6220LE-01_Front___27033.jpg?v=1766552219"},{"product_id":"explore-scientific-62deg-14mm-waterproof-eyepiece","title":"Explore Scientific 62° Series 14mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 62° Series 14mm is a multi-element waterproof eyepiece with a 62-degree apparent field of view, built near-parfocal with the rest of its series. It carries item number EPWP6214LE-01.\u003c\/p\u003e\n\u003cp\u003eFourteen millimetres is a medium-power focal length, and that is the whole point of it. In a 1000mm telescope it gives 71x; in a 750mm Newtonian, 54x; in a 1900mm Maksutov, 136x; in a 988mm refractor, 71x. That band — roughly fifty to a hundred and forty times, depending on the instrument — is where most deep-sky observing actually happens. It is high enough to darken the sky background and pull a globular cluster apart into stars, and low enough that the exit pupil stays comfortable and the object does not race across the field on an undriven mount.\u003c\/p\u003e\n\u003cp\u003eThe 62-degree apparent field is a genuinely useful width without being an ultra-wide design. Explore Scientific make a specific point about it: the field is wide enough, and the contrast clean enough, that you can look slightly to one side of a faint object and let averted vision do its work. That is not marketing so much as physiology — the rods that detect faint light sit away from the centre of the retina, so a faint galaxy or nebula appears when you look beside it rather than at it. An eyepiece that keeps the field clean out to the edge is what makes that technique usable.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers working at medium power:\u003c\/strong\u003e galaxies, globular clusters and the brighter nebulae all respond well in the magnification band a 14mm produces in most telescopes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers building a matched set:\u003c\/strong\u003e the near-parfocal construction means swapping between focal lengths in the series takes a touch of the focuser rather than a full refocus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone who uses averted vision:\u003c\/strong\u003e a clean 62-degree field gives you somewhere to put your gaze while the target stays comfortably inside the view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers in damp climates:\u003c\/strong\u003e the waterproof housing is built for dew-heavy nights and coastal air.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar observers who like the whole disc:\u003c\/strong\u003e at 71x in a metre-focal-length telescope the Moon sits within a 62-degree field with room around it.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e14mm focal length:\u003c\/strong\u003e the medium-power slot in an eyepiece set — 71x in a 1000mm telescope, 136x in a 1900mm one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e62° apparent field of view:\u003c\/strong\u003e wider than a Plössl's typical fifty degrees, without the outer-field demands of an 82° or 100° design.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMulti-element optical design:\u003c\/strong\u003e more than the four elements of a simple Plössl, which is what allows a wider field to stay corrected.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNear-parfocal within the series:\u003c\/strong\u003e changing focal length inside the 62° Series calls for only a small focus correction, which keeps a target in view during the swap.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof housing:\u003c\/strong\u003e sealed against dew, damp air and the accidental soaking that comes with observing outdoors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eContrast optimised for faint targets:\u003c\/strong\u003e Explore Scientific describe the design around detecting dim objects with averted vision, which is a contrast and scatter question more than a magnification one.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMedium-power deep-sky observing — open clusters, globulars, brighter galaxies and emission nebulae.\u003c\/li\u003e\n\u003cli\u003eFull-disc lunar observing in telescopes around a metre of focal length.\u003c\/li\u003e\n\u003cli\u003eWorking through a Messier list, where 14mm is often the first eyepiece tried on a new object.\u003c\/li\u003e\n\u003cli\u003eObserving on an undriven or Dobsonian mount, where a wider apparent field buys drift time between nudges.\u003c\/li\u003e\n\u003cli\u003eDamp-site and coastal observing where a sealed eyepiece holds up better than an unsealed one.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length divided by 14. A 650mm tube gives 46x, a 1200mm SCT gives 86x, a 1900mm Maksutov gives 136x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 14 divided by the telescope's focal ratio. In an f\/5 instrument that is 2.8mm; in an f\/10 it is 1.4mm. Both sit in the range where the eye works comfortably on deep-sky targets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the series:\u003c\/strong\u003e the near-parfocal design is a real convenience when several focal lengths from the 62° Series share a case — the view stays close to focus through a swap.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e threaded filters attach to the bottom of an eyepiece barrel, and the thread that fits follows from the barrel size. Explore Scientific does not state the barrel size for this model on their page, so we would rather check it for you than have you order a filter that does not thread on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 2x extender turns a 14mm into an effective 7mm, which is a straightforward way to add a high-power step without buying a second eyepiece.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish a specification table for this eyepiece.\u003c\/strong\u003e Barrel size, eye relief, field stop diameter, element count, coating specification and weight are all absent from their product page, so those rows read as unpublished here rather than carrying an estimate. If one of them decides it for you — barrel size and eye relief being the two that usually do — ask us and we will put the question to our Explore Scientific rep and give you their answer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e62 degrees is a moderate wide field, not an ultra-wide one.\u003c\/strong\u003e It buys a noticeably roomier view than a Plössl and is easier on the eye position than the widest designs. Observers chasing full immersion look at the 82° and 100° Series instead, and we stock both.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with the right adapter, but the design target is the eye at the eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof means sealed against weather rather than built for submersion in use.\u003c\/strong\u003e The practical benefit is that dew on the outside of the eyepiece wipes off and nothing has migrated inside.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. It slides into the focuser or diagonal, the thumbscrew tightens, and it is working. There is nothing to assemble, collimate or power.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 14. A 1000mm telescope gives 71x, a 1500mm gives 107x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does near-parfocal mean in practice?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eEyepieces in the same series come to focus at close to the same point, so swapping from one focal length to another needs only a small turn of the focuser instead of hunting for focus again in the dark.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit my focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExplore Scientific does not publish the barrel size for this model, so we would rather check it with them than tell you something we cannot verify. Send us a note with your focuser size and we will confirm the fit before you order.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with a Plössl of the same focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe apparent field is wider — 62 degrees against roughly 50 — and the multi-element design is what makes that width possible while keeping the outer field usable. At the same magnification you simply see more sky at once.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs the waterproofing worth anything in normal use?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eOn a dewy night, yes. A sealed eyepiece can be wiped dry and put back to work, and repeated cycles of damp and cold do not gradually fog the interior the way they can with an unsealed housing.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 14mm eyepiece with a 62-degree apparent field, near-parfocal with its series and sealed against weather — the medium-power slot in a set, aimed at faint objects and averted vision. Explore Scientific keeps the detailed figures for this one off their page; if you need one of them before ordering, ask and we will get it from them for you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013376733295,"sku":"EPWP6214LE-01","price":67.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP6214LE-01_Front__18484.jpg?v=1766552225"},{"product_id":"explore-scientific-62-20mm-waterproof-eyepiece","title":"Explore Scientific 62° Series 20mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 62° Series 20mm is a mid-focal-length, argon-purged waterproof eyepiece on a 1.25-inch barrel. It presents a 62° apparent field, carries 14.8mm of eye relief and a 20.9mm field stop, and measures 64mm long by 42mm wide at 5oz (141.75g). The design is a flat-field, multi-element long-eye-relief arrangement, and Explore Scientific describes the series as near-parfocal, so changing focal lengths within it calls for only a slight touch of the focuser.\u003c\/p\u003e\n\u003cp\u003eAt 20mm this is the low-to-medium power end of most focal-length sets. In a 952mm refractor it gives 48x; in a 1200mm Schmidt-Cassegrain, 60x; in a 480mm short refractor, 24x. The 20.9mm field stop is the number that fixes the true field: divide it by your telescope's focal length and multiply by 57.3 to get degrees. That works out to 1.26° in a 952mm scope and 2.49° in a 480mm one.\u003c\/p\u003e\n\u003cp\u003eThe 62° field sits between a classic 50° design and the wide-field 82° and 100° Series. It is wide enough to feel open rather than tunnelled, while staying in a 1.25-inch barrel that fits every standard focuser and diagonal.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers\u003c\/strong\u003e working nebulae, clusters and galaxies at moderate power, where 20mm keeps the exit pupil large and the background sky bright enough to frame an object properly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 14.8mm of eye relief in a long-eye-relief design is enough to take in a good part of the 62° field with glasses on, which is not true of most eyepieces at this price.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers building a matched set:\u003c\/strong\u003e the near-parfocal design across the series means swapping focal lengths does not send you hunting for focus in the dark.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone who uses averted vision:\u003c\/strong\u003e Explore Scientific specifically calls out how easily the eye can wander off-centre in this design, which is exactly the technique that pulls faint detail out of a low-surface-brightness target.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDamp-climate observers:\u003c\/strong\u003e the argon-purged, sealed body is built for dew, humidity and cold nights.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e20mm focal length:\u003c\/strong\u003e a general-purpose power in most telescopes, useful from wide-field sweeping through to framing a large nebula.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e62° apparent field of view:\u003c\/strong\u003e noticeably more open than a 50° design, without the outer-field demands a 100° eyepiece places on both the optics and the observer's eye position.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e14.8mm eye relief in a long-eye-relief layout:\u003c\/strong\u003e comfortable for extended sessions and practical with glasses on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e20.9mm field stop:\u003c\/strong\u003e the published figure that defines true field — a number many manufacturers leave out.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlat field:\u003c\/strong\u003e the design targets sharpness across the field rather than only at centre, so stars near the edge stay stellar.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNear-parfocal within the series:\u003c\/strong\u003e minimal refocusing when swapping between 62° Series focal lengths.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged waterproof construction:\u003c\/strong\u003e inert gas inside a sealed body, which does not support the internal fogging that trapped moist air can cause.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25-inch barrel:\u003c\/strong\u003e the most widely supported eyepiece format there is.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact at 64mm long, 42mm wide and 5oz,\u003c\/strong\u003e so it will not upset the balance of a small refractor or a Dobsonian.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMedium-power deep-sky observing — open clusters, emission nebulae, globular clusters and the larger galaxies.\u003c\/li\u003e\n\u003cli\u003eGeneral sweeping and finding, where 62° and a 20.9mm field stop give a workable search field before you switch to higher power.\u003c\/li\u003e\n\u003cli\u003eLunar observing at moderate magnification, where the whole disc frames comfortably in most telescopes.\u003c\/li\u003e\n\u003cli\u003eObserving with eyeglasses on, where 14.8mm of eye relief is the enabling figure.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal\u003c\/strong\u003e directly. In a 2-inch focuser it seats in a 2-inch to 1.25-inch adapter, which we stock.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 20. A 750mm Newtonian gives 38x; a 952mm refractor 48x; a 1500mm Maksutov 75x; a 2000mm SCT 100x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 20.9mm ÷ telescope focal length × 57.3. That is 1.6° in a 750mm scope and 0.6° in a 2000mm scope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 20mm divided by your telescope's focal ratio. In an f\/6 instrument that is 3.3mm; in an f\/10, 2mm. The larger figure is why 20mm suits deep-sky work in fast telescopes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e 1.25-inch threaded filters — broadband light-pollution, UHC, O-III, lunar and colour — screw into the bottom of the barrel and are a natural pairing at this focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 2x extender turns this into a 10mm-equivalent power while retaining the eye relief characteristics of the 20mm, which is a genuinely useful trick for eyeglass wearers at high power.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish an element count or a coating designation\u003c\/strong\u003e for this eyepiece, so those rows read as unpublished below rather than carrying figures we have inferred. If either matters to your decision, ask and we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe vendor does not state what ships in the box\u003c\/strong\u003e beyond the eyepiece itself. Caps and eyecup arrangements vary across the range, so we would rather not promise a specific accessory list — ask us and we will check the current packing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e62° is a moderate field, not a hyper-wide one.\u003c\/strong\u003e If full immersion is the goal, the 82° and 100° Series are built for that; the 62° Series is built around eye relief, flat field and a compact 1.25-inch format.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof means sealed against weather, not built for submersion in use.\u003c\/strong\u003e The sealing exists so dew, rain and a drop into wet grass are non-events.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIn a very long focal length telescope, 20mm is not a wide-field eyepiece.\u003c\/strong\u003e At 2000mm it delivers 100x over 0.6°. If wide fields in a long scope are what you are after, a longer focal length or a 2-inch format eyepiece is the route, and we can suggest one for the telescope you own.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 1.25-inch focuser or diagonal and is ready immediately. There is nothing to assemble, collimate or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 20. A 1000mm telescope gives 50x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow wide will the view be?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eTake the 20.9mm field stop, divide by your telescope's focal length, multiply by 57.3. A 1000mm telescope gives 1.2°, which is around two and a half full-Moon widths.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. 14.8mm of eye relief in a long-eye-relief design is usable with glasses, though as with any eyepiece the outermost part of the field is easier to take in with them off.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does argon purging accomplish?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe body is sealed and the air inside is replaced with dry argon. Because there is no moist air trapped inside, the internal surfaces will not fog when the eyepiece goes from a warm car to a cold field, and moisture cannot work its way in over the years.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with the 82° Series at a similar focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 82° gives a distinctly wider, more immersive field in a larger and heavier body, often in a 2-inch barrel. The 62° Series trades some of that field for eye relief, compactness and a 1.25-inch fit. Tell us what you observe and which telescope you use and we will give you a straight recommendation.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 20mm eyepiece with a 62° flat field, 14.8mm of eye relief, a published 20.9mm field stop and an argon-purged waterproof body, all in a compact 5oz 1.25-inch package that suits general deep-sky work and eyeglass wearers alike. If you would like help working out which focal lengths would round out your set for the telescope you own, send us its aperture and focal length and we will map it out with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013376766063,"sku":"EPWP6220LE-01","price":67.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP6220LE-01_Front__26872.jpg?v=1766552230"},{"product_id":"explore-scientific-62deg-26mm-waterproof-eyepiece","title":"Explore Scientific 62° Series 26mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 62° Series 26mm is a low-power, wide-field eyepiece in an argon-purged waterproof housing with a 1.25-inch barrel. Explore Scientific publishes a 62° apparent field, 19.3mm of eye relief and a 27.3mm field stop, in a body 76mm long and 50mm wide weighing 8.2oz (323.47g).\u003c\/p\u003e\n\u003cp\u003eThat 27.3mm field stop is the figure to pay attention to. The clear aperture of a 1.25-inch barrel puts a hard ceiling of roughly 27mm on how much sky any 1.25-inch eyepiece can pass, so at 26mm and 62° this eyepiece is sitting at the physical limit of the format. There is no wider true field available in a 1.25-inch barrel — going wider means going to 2 inches.\u003c\/p\u003e\n\u003cp\u003eExplore Scientific describes the series as near-parfocal with a flat field, which means swapping between focal lengths in the range needs little or no refocusing, and star images hold their shape from the centre out toward the edge. The 19.3mm of eye relief is generous for the format and makes observing with eyeglasses on practical.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers\u003c\/strong\u003e who want the widest true field a 1.25-inch focuser can deliver — large open clusters, the Pleiades, the sword of Orion, sweeping along the Milky Way.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian owners:\u003c\/strong\u003e a wide low-power field is what makes finding and framing objects on an undriven mount workable, and it buys drift time between nudges.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 19.3mm of eye relief takes in the full 62° field with spectacles in place.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers assembling a matched set:\u003c\/strong\u003e the near-parfocal design means changing focal lengths within the series barely disturbs focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone observing in dew:\u003c\/strong\u003e the sealed, gas-purged construction is built for damp nights.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOwners of telescopes with 1.25-inch focusers\u003c\/strong\u003e who want maximum field without moving to a 2-inch focuser and diagonal.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e26mm focal length with a 62° apparent field:\u003c\/strong\u003e a genuinely wide low-power view, noticeably more open than a 50° Plössl of the same focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e27.3mm field stop:\u003c\/strong\u003e effectively the maximum a 1.25-inch barrel can pass, which is what makes this the widest true field in the format.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e19.3mm eye relief:\u003c\/strong\u003e long enough for comfortable extended sessions and for observing with glasses on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlat-field optics:\u003c\/strong\u003e Explore Scientific specifies strong contrast and image quality held across the field rather than only at centre.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNear-parfocal within the series,\u003c\/strong\u003e so focal length changes need minimal refocusing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof, argon-purged construction\u003c\/strong\u003e consistent with the sealed Explore Scientific waterproof eyepiece range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ barrel\u003c\/strong\u003e fitting any standard focuser or diagonal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished dimensions:\u003c\/strong\u003e 76mm long, 50mm wide, 8.2oz (323.47g).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLow-power sweeping of the Milky Way and large open clusters.\u003c\/li\u003e\n\u003cli\u003eLocating targets before switching to a higher-power eyepiece — the wide field makes the initial find far easier.\u003c\/li\u003e\n\u003cli\u003eLarge emission nebulae, particularly with a narrowband or UHC filter in the barrel.\u003c\/li\u003e\n\u003cli\u003eUndriven Dobsonian and alt-azimuth observing, where field width converts directly into time on target.\u003c\/li\u003e\n\u003cli\u003eComfortable long sessions and outreach nights where observers cycle through the eyepiece quickly.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal.\u003c\/strong\u003e In a 2-inch focuser it takes a 2-inch to 1.25-inch adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 26. A 714mm refractor gives 27x, a 1200mm SCT gives 46x, a 1500mm Dobsonian gives 58x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 27.3mm field stop ÷ telescope focal length × 57.3. In a 714mm telescope that works out to about 2.2°; in a 1200mm telescope about 1.3°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 26mm ÷ the telescope's focal ratio. In an f\/5 instrument that is 5.2mm, which suits a dark site well; in an f\/10 instrument it is 2.6mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e Explore Scientific does not publish the filter thread specification for this eyepiece, so we are not quoting one. If you plan to run a UHC or O-III filter in it, ask us and we will confirm the thread with our rep first.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the range:\u003c\/strong\u003e the near-parfocal design across the 62° Series means a set holds focus and eye position from one focal length to the next.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e26mm is close to the practical ceiling for a 1.25-inch eyepiece.\u003c\/strong\u003e A longer focal length in this barrel size would show a larger exit pupil but no more sky, because the 27.3mm field stop is already at the limit of what the barrel passes. If you want a wider true field than this, a 2-inch eyepiece is the route, and we stock those.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIn a fast telescope the exit pupil gets large.\u003c\/strong\u003e At f\/4 a 26mm eyepiece produces a 6.5mm exit pupil, which can exceed the dilated pupil of an older eye and effectively waste part of the aperture. A shorter focal length restores it, and we can suggest one for your focal ratio.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish the element count, coating specification or filter thread\u003c\/strong\u003e for this model, so those rows read \"Not published by vendor\" below rather than carrying an estimate. If one of them matters to your decision, ask and we will confirm it with our rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnder bright suburban skies a large exit pupil shows the sky glow as well as the target.\u003c\/strong\u003e That is site conditions rather than optics, and a light-pollution or narrowband filter is the usual answer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAt 8.2oz it is a moderate weight\u003c\/strong\u003e for a 1.25-inch eyepiece, which is worth a thought on a small refractor where balance shifts easily. Rebalancing the tube in its rings takes a moment and settles it.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 1.25-inch focuser or diagonal and is ready to use. Nothing to assemble, collimate or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 26. A 1000mm telescope gives 38x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much sky will I actually see?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eTake the 27.3mm field stop, divide by your telescope's focal length and multiply by 57.3. In a 900mm telescope that is about 1.7° — roughly three and a half lunar diameters.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it better than a 25mm Plössl?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt shows a wider apparent field at 62° against roughly 50°, carries substantially more eye relief at 19.3mm, and is sealed against moisture. Whether that is worth the difference depends on how you observe, and we are happy to talk it through.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. 19.3mm of eye relief is enough to take in the whole field with spectacles in place.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit a 2-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eWith a 2-inch to 1.25-inch adapter, yes. Many 2-inch diagonals include one.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it good for a Dobsonian?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt is one of the more useful focal lengths for one. The wide field makes finding objects manageable without a driven mount, and a target stays in view longer between nudges.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 26mm waterproof eyepiece with a 62° apparent field, 19.3mm of eye relief and a 27.3mm field stop that sits at the physical limit of the 1.25-inch format — the widest true field the barrel size allows, in a sealed body that handles dew. If you would like help pairing it with the focal lengths you already own, send us your telescope's focal length and what is in your case and we will work it out with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013376798831,"sku":"EPWP6226LE-01","price":77.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP6226LE-01_Front__98248.jpg?v=1766552237"},{"product_id":"explore-scientific-62deg-32mm-waterproof-eyepiece","title":"Explore Scientific 62deg 32mm Waterproof Eyepiece","description":"\u003cp style=\"margin: 0px 0px 15px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-stretch: inherit; font-size: 14px; line-height: 1.8em; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eExplore Scientific Waterproof Eyepieces - Comfort, Quality, Value. The Explore Scientific 62° Series  eyepieces are excellent flat-field multi-element oculars that can transform your visual astronomy experience. With an apparent field of view of 62 degrees and near par focal design, these eyepieces offer incredible value in a very nice eyepiece. \u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px 0px 15px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-stretch: inherit; font-size: 14px; line-height: 1.8em; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eAnother great benefit of these eyepieces is the excellent contrast and ease with which you can gaze, not directly at an object, but slightly to either side. This skill, called using averted vision, is especially helpful when observing faint objects, because using averted vision puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.\u003c\/span\u003e\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013376831599,"sku":"EPWP6232LE-01","price":115.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP6232LE-01_Front__65971.jpg?v=1766552244"},{"product_id":"explore-scientific-62-40mm-waterproof-eyepiece","title":"Explore Scientific 62deg 40mm Waterproof Eyepiece","description":"\u003cp style=\"margin: 0px 0px 15px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-stretch: inherit; font-size: 14px; line-height: 1.8em; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eExplore Scientific Waterproof Eyepieces - Comfort, Quality, Value. The Explore Scientific 62° Series  eyepieces are excellent flat-field multi-element oculars that can transform your visual astronomy experience. With an apparent field of view of 62 degrees and near par focal design, these eyepieces offer incredible value in a very nice eyepiece. \u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px 0px 15px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-stretch: inherit; font-size: 14px; line-height: 1.8em; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eAnother great benefit of these eyepieces is the excellent contrast and ease with which you can gaze, not directly at an object, but slightly to either side. This skill, called using averted vision, is especially helpful when observing faint objects, because using averted vision puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.\u003c\/span\u003e\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013376864367,"sku":"EPWP6240LE-01","price":221.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/62Degree_40mm_EPWP6240LE-01__96574.jpg?v=1766552250"},{"product_id":"explore-scientific-3mm-52-series-waterproof-eyepiece","title":"Explore Scientific 52° Series 3mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 52° Series 3mm is the shortest focal length in the 52° range — a six-element, three-group eyepiece in an argon-purged waterproof housing with a 1.25-inch double-taper barrel. Explore Scientific publishes 15mm of eye relief, a 2.7mm field stop, EMD (Enhanced Multi-Layer Deposition) coatings on every lens-to-air surface, and edge-blackened elements. It measures 90.9mm long by 43mm wide and weighs 204.1 grams (7.2 oz.).\u003c\/p\u003e\n\u003cp\u003eAt 3mm this is an extreme-magnification eyepiece. Explore Scientific quotes 160X on an ED80 and up to 405X on an ED152. The practical effect is that this eyepiece is chosen for a specific job on a specific kind of night: a steady atmosphere, a planet or a tight double star, and an aperture large enough to have detail left to resolve at that power.\u003c\/p\u003e\n\u003cp\u003eThe 52° apparent field is deliberately modest. What the series buys with that restraint is edge correction and value — a flat, well-behaved field across its width rather than a panoramic one, in a sealed body that shrugs off dew.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary observers\u003c\/strong\u003e chasing the finest scale of detail their aperture can show: festoons in the Jovian cloud belts, the Encke minimum, surface markings on Mars near opposition.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble-star observers\u003c\/strong\u003e working on tight pairs, where raw magnification separates components that blur together at lower power.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar observers\u003c\/strong\u003e examining individual craterlets, rilles and terracing along the terminator.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOwners of short-focal-length telescopes:\u003c\/strong\u003e in an f\/6 80mm at 480mm, 3mm gives 160x — a genuinely useful high power that a longer eyepiece could not reach without a focal extender.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers in damp climates:\u003c\/strong\u003e the O-ring sealed, argon-filled body is tested under 1 metre of water for 30 minutes, and argon does not condense internally the way trapped humid air does.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e6 elements in 3 groups, edge blackened:\u003c\/strong\u003e the blackening on the ground edges of each element absorbs light that would otherwise bounce around inside the barrel and lift the background.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEMD coatings on all lens-to-air surfaces:\u003c\/strong\u003e higher transmission and better contrast, which matters most at high magnification where the image is already dim.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e15mm eye relief at 3mm focal length:\u003c\/strong\u003e notable, because eye relief in a simple short-focus design usually scales with focal length and would otherwise be a few millimetres here.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2.7mm field stop:\u003c\/strong\u003e the figure that defines true field — divide it by your telescope's focal length and multiply by 57.3 to get degrees.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged, O-ring sealed body:\u003c\/strong\u003e tested under 1 metre of water for 30 minutes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ double-taper barrel:\u003c\/strong\u003e the taper gives a thumbscrew something to catch on, so the eyepiece resists being pulled out of a diagonal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 1.25-inch filter thread\u003c\/strong\u003e (1.125-inches x 42 TPI).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemovable flip-down soft silicone eyecup\u003c\/strong\u003e and slide-on caps top and bottom.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLaser-engraved markings:\u003c\/strong\u003e focal length, series, serial number and brand.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished dimensions:\u003c\/strong\u003e 90.9mm long, 43mm wide, 204.1 grams (7.2 oz.).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMaximum-power lunar and planetary observing on nights of steady seeing.\u003c\/li\u003e\n\u003cli\u003eSplitting close double stars.\u003c\/li\u003e\n\u003cli\u003eDetailed work on small bright deep-sky objects — the brighter planetary nebulae, the cores of globular clusters.\u003c\/li\u003e\n\u003cli\u003eReaching high magnification in short-focal-length telescopes without adding a focal extender to the train.\u003c\/li\u003e\n\u003cli\u003eCompleting a matched 52° Series set so eye position and field character stay consistent across focal lengths.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal directly.\u003c\/strong\u003e In a 2-inch focuser it takes a 2-inch to 1.25-inch adapter, which we stock.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 3. A 480mm f\/6 refractor gives 160x; a 952mm f\/7.5 gives 317x; a 1200mm SCT gives 400x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e takes standard 1.25-inch threaded filters. Colour and neutral-density filters are the usual planetary companions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 3mm eyepiece is already at the short end, and pairing it with a 2x or 3x extender goes beyond the useful magnification of nearly any aperture. Longer eyepieces in the series are the better partners for an extender.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e aperture divided by magnification — in an f\/7.5 telescope the exit pupil is 0.4mm, which is small and dim by design at this power.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 15mm is workable, though observers who need more can look at the 72° ED and 92° Series, which are built around longer eye relief.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e3mm is the highest-power eyepiece most telescopes can meaningfully use, and the atmosphere decides when.\u003c\/strong\u003e On a steady night in a well-cooled telescope it shows what the aperture can do; on a turbulent night a 5mm or 7mm will show more. It is the eyepiece for the good nights, and a well-chosen mid-range focal length covers the rest.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe exit pupil at this focal length is very small.\u003c\/strong\u003e Around 0.4mm in an f\/7.5 instrument, which can make floaters in your own eye visible. That is normal physiology at high magnification rather than a fault in the optics.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 52° field is a corrected field rather than a wide one.\u003c\/strong\u003e If an immersive view is the goal, the 68°, 82°, 92° and 100° Series cover that ground; the 52° Series is built around edge sharpness and value.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof means sealed against immersion, not intended for use underwater.\u003c\/strong\u003e The 1 metre \/ 30 minute rating exists so that dew, rain and a drop into wet grass are non-events.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOn an undriven mount at this power a target crosses the field quickly.\u003c\/strong\u003e A tracking mount or a driven Dobsonian platform is what makes 3mm relaxing rather than a chase, and we stock both.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 1.25-inch focuser or diagonal and is ready immediately. There is nothing to assemble, collimate or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 3. A 900mm telescope gives 300x. Explore Scientific quotes 160X on an ED80 and up to 405X on an ED152.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill my telescope actually support that much magnification?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eAperture and atmosphere both set limits. A large, well-cooled telescope on a steady night will use it fully; a small aperture or an unsettled sky will not. Send us your telescope's aperture and focal length and we will tell you honestly whether 3mm is the right end of the range for it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use filters with it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. Standard 1.25-inch threaded filters screw into the bottom of the barrel — the thread is 1.125-inches x 42 TPI.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does argon purging achieve?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe interior is sealed with O-rings and filled with dry argon in place of air. With no water vapour inside, the internal surfaces have nothing to fog with when the temperature drops.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow is it different from a Plössl at a similar price?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSix elements against four, a slightly wider 52° field, EMD coatings on every air-to-glass surface, edge-blackened elements, and a sealed argon-purged housing. At 3mm the eye relief difference is the one you notice first — a 3mm Plössl offers very little.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it work for astrophotography?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt is a visual eyepiece. Eyepiece-projection imaging is possible with the right adapter, but the design target is the eye.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 3mm argon-purged waterproof eyepiece with six elements in three groups, EMD coatings throughout, 15mm of eye relief and a standard 1.25-inch filter thread — the top of the 52° Series magnification range, built for steady nights on the Moon, the planets and close doubles. If you would like help deciding which focal lengths round out a set for the telescope you own, send us its aperture and focal length and we will map it out with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013466386543,"sku":"EPWP5203–01","price":96.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP5203-01_1_1663x__69129.jpg?v=1766553847"},{"product_id":"explore-scientific-4-5mm-52-series-waterproof-eyepiece","title":"Explore Scientific 52° Series 4.5mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 52° Series 4.5mm is a short focal length, argon-purged waterproof eyepiece with a 1.25-inch double-taper barrel. Six elements in three groups sit behind EMD (Enhanced Multi-Layer Deposition) coatings on every lens-to-air surface, and the edges of the elements are blackened to hold contrast. At 4.5mm it sits at the high-magnification end of the 52° range — in a 988mm refractor it yields 220x, in a 1200mm SCT 267x.\u003c\/p\u003e\n\u003cp\u003eThe 52° apparent field is a flat, well-corrected view rather than a wide one. Against a comparably priced Plössl, the gain is in edge correction and in the sealed, gas-purged housing.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary and lunar observers:\u003c\/strong\u003e 4.5mm is where surface detail on Mars, the Jovian belts and the Cassini division live, seeing permitting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble-star observers:\u003c\/strong\u003e the 15mm eye relief and 4.1mm field stop make splitting close pairs comfortable rather than a squint.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact deep-sky observers:\u003c\/strong\u003e planetary nebulae and globular cores scale up to fill the field, and the background sky darkens as magnification rises.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone observing in dew or damp air:\u003c\/strong\u003e the O-ring sealed, argon-filled body is built for it.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e6 elements in 3 groups:\u003c\/strong\u003e edge-blackened to suppress internal reflections and scatter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEMD coatings on all lens-to-air surfaces:\u003c\/strong\u003e raises transmission and holds contrast on low-surface-brightness targets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged, O-ring sealed:\u003c\/strong\u003e tested under 1 metre of water for 30 minutes. Argon does not support internal fogging the way trapped air does.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e15mm eye relief:\u003c\/strong\u003e workable for most observers at this focal length, where eye relief is usually the first thing sacrificed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e4.1mm field stop:\u003c\/strong\u003e defines the true field — divide by your telescope's focal length to get it in degrees.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ double-taper barrel:\u003c\/strong\u003e the taper resists the eyepiece being pulled out of a diagonal by a slipping thumbscrew.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 1.25-inch filter thread\u003c\/strong\u003e (1.125″ x 42 TPI) for lunar, planetary and narrowband filters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemovable flip-down silicone eyecup\u003c\/strong\u003e and slide-on caps top and bottom.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLaser-engraved markings:\u003c\/strong\u003e focal length, series, serial number and brand.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHigh-power visual observing of the Moon, planets and double stars.\u003c\/li\u003e\n\u003cli\u003eBright, compact deep-sky objects — planetary nebulae, globular cluster cores, small galaxies.\u003c\/li\u003e\n\u003cli\u003eFilling out a focal-length set alongside longer 52° Series eyepieces for a consistent view across the range.\u003c\/li\u003e\n\u003cli\u003eDamp-climate and dew-heavy observing sites where a sealed eyepiece earns its keep.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal.\u003c\/strong\u003e No adapter needed. In a 2-inch focuser it needs a 2-inch to 1.25-inch adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilter thread:\u003c\/strong\u003e accepts standard 1.25-inch threaded filters — lunar, neutral density, colour and narrowband.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 4.5. An 80mm f\/6 (480mm) gives 107x; a 152mm f\/6.5 (988mm) gives 220x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e pairing a 2x, 3x or 5x extender with a 4.5mm pushes past the useful magnification of most apertures. Longer focal lengths in the series are the better partner for an extender.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 15mm of eye relief is usable but not generous. If you observe with glasses on, the 72° ED Series carries more.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAperture sets the ceiling on 4.5mm.\u003c\/strong\u003e Around 220x in a 6-inch and 267x in an 8-inch, this is a night-dependent eyepiece — steady seeing rewards it, turbulent seeing will not. It is the eyepiece you reach for on the good nights.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 52° field is a corrected field, not a wide one.\u003c\/strong\u003e If immersion is what you are after, the 68°, 82° and 100° Series cover that; the 52° Series is built around edge sharpness and value.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShort focal length means a small exit pupil.\u003c\/strong\u003e In an f\/6.5 scope the exit pupil is 0.69mm, so floaters in your own eye can become visible — a normal effect of high magnification, not a fault in the optics.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof covers immersion, not submersion in use.\u003c\/strong\u003e The 1 metre \/ 30 minute rating is there so dew, rain and a dropped eyepiece in wet grass are non-events.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops straight into any 1.25-inch focuser or diagonal and is ready to use. There is nothing to assemble, collimate or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 4.5. A 1000mm telescope gives 222x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use filters with it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. It takes any standard 1.25-inch threaded filter, which screws into the bottom of the barrel.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow is it different from a Plössl at a similar price?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSix elements against a Plössl's four, a wider 52° field against roughly 50°, EMD coatings on every air-to-glass surface, and a sealed argon-purged body. The practical difference shows at the edge of the field and in damp conditions.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it work with my Dobsonian or SCT?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes — any telescope with a 1.25-inch focuser, or a 2-inch focuser with a 1.25-inch adapter. On longer focal length instruments 4.5mm produces very high magnification, so it will be a good-seeing eyepiece.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it work for astrophotography?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThis is a visual eyepiece. Eyepiece-projection imaging is possible with the right adapter, but it is not what the eyepiece is built for.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a sealed, argon-purged 4.5mm eyepiece with a flat 52° field, 15mm of eye relief and a standard 1.25-inch filter thread — the high-power end of a series built around edge correction and durability. If you are not sure which focal lengths would round out your set for the telescope you own, send us your scope's aperture and focal length and we will work it out with you.\u003c\/p\u003e\n","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013466419311,"sku":"EPWP5245–01","price":96.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP5245-01_3_1663x__19766.jpg?v=1766553854"},{"product_id":"explore-scientific-52-6-5mm-waterproof-eyepiece","title":"EXPLORE SCIENTIFIC 52 deg 6.5MM WATERPROOF EYEPIECE","description":"\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px 0px 0.9375em; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eMid-range high power eyepieces like the 6.5mm are instrumental when transitioning through magnifications to observe an object until it is best seen. There are several aspects that have to come together when observing at high powers: good-to-perfect atmospheric seeing conditions; telescope optics that are collimated; a telescope that is acclimated to the ambient temperature; brightness and size of the object being observed are just a few aspects to consider. The observing challenges are high, but the rewards of observing at high power with razor sharp views are unforgettable.\u003c\/p\u003e\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px 0px 0.9375em; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eExplore Scientific Waterproof Eyepieces - Comfort, Quality, Value. The Explore Scientific 52° Series eyepieces are excellent flat-field multi-element oculars that can transform your visual astronomy experience. With an apparent field of view of 52 degrees, these eyepieces offer incredible value in a very nice eyepiece. Expect exceptional quality and value versus a comparably priced Plossol.\u003c\/p\u003e\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eAnother great benefit of these eyepieces is the excellent contrast and ease with which you can gaze, not directly at an object, but slightly to either side. This skill, called using averted vision, is especially helpful when observing faint objects, because using averted vision puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013466484847,"sku":"EPWP5265–01","price":96.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP5265-01_3_1663x__70299.jpg?v=1766553860"},{"product_id":"explore-scientific-10mm-52-series-waterproof-eyepiece","title":"EXPLORE SCIENTIFIC 10MM 52 deg SERIES WATERPROOF EYEPIECE","description":"\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px 0px 0.9375em; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eEyepieces at or near the 10mm range are often considered a mandatory focal length in your collection, as this focal length range is departure point from medium power eyepieces for most telescopes for amateur astronomers. Fainter deep sky objects that do not have the inherent brightness to be observed at higher powers are often perfect for a 10mm. Explore Scientific Waterproof Eyepieces - Comfort, Quality, Value. The Explore Scientific 52° Series„¢ eyepieces are excellent flat-field multi-element oculars that can transform your visual astronomy experience. With an apparent field of view of 52 degrees, these eyepieces offer incredible value in a very nice eyepiece. Expect exceptional quality and value versus a comparably priced Plossl.\u003c\/p\u003e\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eAnother great benefit of these eyepieces is the excellent contrast and ease with which you can gaze, not directly at an object, but slightly to either side. This skill, called using averted vision, is especially helpful when observing faint objects, because using averted vision puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013466517615,"sku":"EPWP5210–01","price":96.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP5210-01_1_1663x__81546.jpg?v=1766553867"},{"product_id":"explore-scientific-52mm-15mm-waterproof-eyepiece","title":"EXPLORE SCIENTIFIC 52mm 15MM WATERPROOF EYEPIECE","description":"\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px 0px 0.9375em; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eSolidly in the mid-magnification range for most amateur telescopes, the 15mm is a true workhorse for visual observers. If you love deep sky observing, eyepieces in this focal length range not only give healthy increases in magnification, but the contrast enhancement of giving a darker background sky can make all the difference of how galaxies and nebulae appear under suburban skies.\u003c\/p\u003e\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px 0px 0.9375em; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eExplore Scientific Waterproof Eyepieces - Comfort, Quality, Value. The Explore Scientific 52° Series eyepieces are excellent flat-field multi-element oculars that can transform your visual astronomy experience. With an apparent field of view of 52 degrees, these eyepieces offer incredible value in a very nice eyepiece. Expect exceptional quality and value versus a comparably priced Plossol.\u003c\/p\u003e\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eAnother great benefit of these eyepieces is the excellent contrast and ease with which you can gaze, not directly at an object, but slightly to either side. This skill, called using averted vision, is especially helpful when observing faint objects, because using averted vision puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013466550383,"sku":"EPWP5215-01","price":96.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP5215-01_3_1663x__48809.jpg?v=1766553873"},{"product_id":"explore-scientific-20mm-52-series-waterproof-eyepiece","title":"EXPLORE SCIENTIFIC 20MM 52 deg SERIES WATERPROOF EYEPIECE","description":"\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px 0px 0.9375em; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eOften considered the perfect mid-range focal length for most amateur telescopes, the 20mm on the ED127 at f7.5 produces a 1 degree true field of view. Perfect for the Messier Marathon, or running down the Herschel Catalog. The 20mm 52° Series is also a good selection for most binoviewers with its relatively small size and magnification range.\u003c\/p\u003e\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px 0px 0.9375em; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eExplore Scientific Waterproof Eyepieces - Comfort, Quality, Value. The Explore Scientific 52° Series eyepieces are excellent flat-field multi-element oculars that can transform your visual astronomy experience. With an apparent field of view of 52 degrees, these eyepieces offer incredible value in a very nice eyepiece. Expect exceptional quality and value versus a comparably priced Plossl.\u003c\/p\u003e\u003cp style=\"overflow-wrap: break-word; word-break: break-word; box-sizing: border-box; margin: 0px; font-size: 0.875em; font-family: Roboto, HelveticaNeue, \" helvetica neue arial sans-serif rgb background-color:=\"\"\u003eAnother great benefit of these eyepieces is the excellent contrast and ease with which you can gaze, not directly at an object, but slightly to either side. This skill, called using averted vision, is especially helpful when observing faint objects, because using averted vision puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013466583151,"sku":"EPWP5220–01","price":96.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP5220-01_3_1663x__95165.jpg?v=1766553880"},{"product_id":"explore-scientific-25mm-52-series-waterproof-eyepiece","title":"Explore Scientific 52° Series 25mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 52° Series 25mm is the long-focal-length, low-power end of the 52° range: an argon-purged, O-ring sealed eyepiece with a 1.25-inch double-taper barrel, built around four elements in two groups with EMD (Enhanced Multi-Layer Deposition) coatings on every lens-to-air surface and blackened element edges.\u003c\/p\u003e\n\u003cp\u003eThe published figures are unusually complete for an eyepiece at this price. Eye relief is 16.4mm, the field stop measures 18.2mm, the body is 67.7mm long and 43mm wide, and it weighs 181.4 grams (6.4 oz). The 18.2mm field stop is the number that matters most in practice: it fixes the true field at 57.3 multiplied by 18.2 and divided by your telescope's focal length. In a 1000mm telescope that is 1.04°; in a 663mm refractor, 1.57°.\u003c\/p\u003e\n\u003cp\u003eAt 25mm this is a finder and framing eyepiece — the one that locates the object, shows the whole of a large cluster, and hands over to something shorter when detail is the goal.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers working at low power:\u003c\/strong\u003e open clusters, large nebulae and the Milky Way star fields all want a wide true field and a bright image more than they want magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone who starts a search at low power:\u003c\/strong\u003e 25mm gives the widest sweep in the series, which is what makes star-hopping to a faint target practical.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 16.4mm of eye relief at 25mm is generous, and the flip-down silicone eyecup folds back to let spectacle lenses sit close enough to take in the field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers in damp climates:\u003c\/strong\u003e the O-ring sealed, argon-purged body is tested under one metre of water for thirty minutes, so dew and drizzle are not events.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers filling out a focal-length set\u003c\/strong\u003e who want the same coatings, barrel and eye position across the range.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e4 elements in 2 groups, edge-blackened:\u003c\/strong\u003e a simple, high-transmission layout with few internal surfaces to scatter light, and blackened edges to keep stray light out of the field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEMD coatings on all lens-to-air surfaces:\u003c\/strong\u003e every air-glass boundary is coated rather than just the outer ones, which is where transmission and contrast on faint extended objects are won or lost.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e16.4mm eye relief:\u003c\/strong\u003e comfortable for long sessions and workable with glasses on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e18.2mm field stop:\u003c\/strong\u003e the physical aperture that defines the true field — a known figure rather than something to be inferred.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e52° apparent field:\u003c\/strong\u003e a corrected, flat field rather than a panoramic one, which is the design priority of this series.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ O.D. double-taper barrel:\u003c\/strong\u003e the taper gives a thumbscrew something to bite against, so the eyepiece resists being pulled out of a diagonal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eO-ring sealed and argon gas purged:\u003c\/strong\u003e tested under 1 metre of water for 30 minutes. Argon inside the body does not condense the way trapped humid air does.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 1.25-inch filter thread\u003c\/strong\u003e (1.125-inches x 42 TPI) at the base of the barrel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemovable flip-down soft silicone eyecup\u003c\/strong\u003e and slide-on caps top and bottom.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e67.7mm long, 43mm wide, 181.4 grams (6.4 oz):\u003c\/strong\u003e light enough that it does not upset the balance of a small refractor or a Dobsonian.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLaser-engraved markings:\u003c\/strong\u003e focal length, series, serial number and brand.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLow-power deep-sky observing — open clusters, large emission nebulae, the brighter galaxies.\u003c\/li\u003e\n\u003cli\u003eLocating objects before switching to a higher-power eyepiece.\u003c\/li\u003e\n\u003cli\u003eWide-field sweeping of the Milky Way and rich star fields.\u003c\/li\u003e\n\u003cli\u003eDamp-site and coastal observing where a sealed eyepiece keeps working.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal\u003c\/strong\u003e directly. In a 2-inch focuser it takes a 2-inch to 1.25-inch adapter, which most 2-inch diagonals already include.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 25. A 663mm refractor gives 27x, a 1219mm Newtonian 49x, a 2000mm Schmidt-Cassegrain 80x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 57.3 × 18.2 ÷ telescope focal length. That is 1.57° at 663mm, 0.86° at 1219mm and 0.52° at 2000mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 25 ÷ the telescope's focal ratio. An f\/5.9 Dobsonian gives 4.2mm, an f\/6.5 refractor 3.8mm, an f\/10 Schmidt-Cassegrain 2.5mm. At f\/4 the exit pupil reaches 6.25mm, which is at the edge of what a dark-adapted eye takes in.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e the 1.125-inch x 42 TPI thread accepts any standard 1.25-inch filter — broadband, narrowband, lunar or colour. Narrowband nebula filters pair particularly well with a 25mm on a rich field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 2x extender turns this into an effective 12.5mm while keeping the eye relief of the 25mm, which is a genuinely useful pairing at the long end of a series.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the series:\u003c\/strong\u003e the barrel, filter thread and eyecup are shared across the 52° Series, so a matched set behaves consistently as focal lengths change.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 52° field is a corrected field, not a wide one.\u003c\/strong\u003e The design priority here is edge sharpness and value rather than immersion. The 68°, 82° and 92° ranges cover the panoramic end, and we stock those if that is what you are after.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFour elements in two groups is a simple layout.\u003c\/strong\u003e That is a strength for transmission and weight, and it is also why the apparent field stays at 52° rather than pushing wider — wide fields need more glass.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIn a fast telescope the exit pupil gets large.\u003c\/strong\u003e Below about f\/5 the 25mm produces an exit pupil wider than many adult eyes dilate to, so part of the light cone falls on the iris rather than entering the eye. A shorter focal length recovers it, and we can suggest one that matches your focal ratio.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof means sealed against immersion, not built for use underwater.\u003c\/strong\u003e The 1 metre, 30 minute rating exists so that dew, rain and an eyepiece dropped in wet grass are non-events.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe double-taper barrel is a compression-friendly shape.\u003c\/strong\u003e It works with both thumbscrew and compression-ring holders, so no adapter change is needed for either.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops straight into any 1.25-inch focuser or diagonal and is ready to use. There is nothing to assemble, collimate or adjust, and the caps and eyecup come off by hand.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 25. A 1000mm telescope gives 40x; a 1219mm Dobsonian gives 49x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow wide a piece of sky will I actually see?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 18.2mm field stop settles that exactly: 57.3 × 18.2 ÷ your telescope's focal length. In a 1000mm telescope that is 1.04°, or about twice the width of the full Moon.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. 16.4mm of eye relief is enough for most spectacle wearers, and the flip-down silicone eyecup folds out of the way so the lens can sit close to the eye lens.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use filters with it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. Any standard 1.25-inch threaded filter screws into the base of the barrel — the thread is 1.125 inches x 42 TPI, which is the common standard.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare to a Plössl of the same focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eBoth are four-element designs, so transmission is in the same territory. The differences are the sealed argon-purged housing, EMD coatings on every lens-to-air surface, the double-taper barrel and the published 16.4mm eye relief, which is more than a 25mm Plössl typically offers. In practice the sealing and the eye comfort are what you notice night to night.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 25mm argon-purged eyepiece with a 52° corrected field, 16.4mm of eye relief, an 18.2mm field stop and a standard 1.25-inch filter thread, at 181.4 grams — the low-power, wide-true-field end of a series built around edge sharpness and durability. If you would like help working out which focal lengths would round out your set for the telescope you own, send us its aperture and focal length and we will map it out with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013466615919,"sku":"EPWP5225–01","price":110.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP5220-01_3_1663x__26580.jpg?v=1766553887"},{"product_id":"explore-scientific-30mm-52-series-waterproof-eyepiece","title":"Explore Scientific 52° Series 30mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 52° Series 30mm is the long focal length end of the 52° range: a four-element, argon-purged waterproof eyepiece in a 1.25-inch double-taper barrel, with a 27.2mm field stop and 19.9mm of eye relief. At 75.5mm long, 47.8mm wide and 204.1 grams (7.2 oz.) it is a light eyepiece for what it delivers.\u003c\/p\u003e\n\u003cp\u003eA 27.2mm field stop is close to the physical limit of what a 1.25-inch barrel can pass, and that is what makes this focal length interesting. In a 1200mm telescope the true field works out to about 1.3°; in an 826mm refractor, about 1.9°. Magnification is the telescope's focal length divided by 30, so 27.5x in that 826mm refractor and 40x in the 1200mm one — low power, wide field, and a bright image.\u003c\/p\u003e\n\u003cp\u003eFour elements in two groups keep the light path simple, every lens-to-air surface carries EMD (Enhanced Multi-Layer Deposition) coatings, and the element edges are blackened to hold contrast against internal reflections. The housing is O-ring sealed and argon-purged, tested under 1 metre of water for 30 minutes.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers working at low power:\u003c\/strong\u003e 30mm produces a large exit pupil, which is what makes faint extended objects such as galaxies and large nebulae stand out from the background.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who locate by star-hopping:\u003c\/strong\u003e a 1.3° field at 1200mm is a wide window to find things in before switching to higher magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOpen cluster and Milky Way observers,\u003c\/strong\u003e where the whole object fitting inside the field is the point.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 19.9mm of eye relief is generous, and enough that the full 52° field stays visible with spectacles on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone observing in dew, damp air or coastal humidity,\u003c\/strong\u003e where a sealed argon-filled body earns its place.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e4 elements in 2 groups, edge-blackened:\u003c\/strong\u003e a simple, high-transmission path with the element edges treated to suppress scatter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEMD coatings on all lens-to-air surfaces:\u003c\/strong\u003e Enhanced Multi-Layer Deposition, applied to raise throughput and hold contrast on low-surface-brightness targets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e27.2mm field stop:\u003c\/strong\u003e near the maximum a 1.25-inch barrel can carry, which is what gives this eyepiece its true field. Divide 57.3 × 27.2 by your telescope's focal length for the field in degrees.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e19.9mm eye relief:\u003c\/strong\u003e comfortable for extended sessions and workable with glasses.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ O.D. double-taper barrel:\u003c\/strong\u003e the taper resists the eyepiece being drawn out of a diagonal by a thumbscrew that is not quite tight.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon-purged and O-ring sealed:\u003c\/strong\u003e tested under 1 metre of water for 30 minutes. Argon does not carry the moisture that trapped air does, so internal fogging has nothing to condense from.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 1.25-inch filter thread\u003c\/strong\u003e (1.125-inches x 42 TPI) at the base of the barrel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemovable flip-down soft silicone eyecup,\u003c\/strong\u003e with slide-on lens caps top and bottom.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical glass, aluminium, steel and silicone rubber construction,\u003c\/strong\u003e at 204.1 grams (7.2 oz.).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLaser-engraved markings:\u003c\/strong\u003e focal length, series, serial number and brand.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLow-power sweeping of the Milky Way, large open clusters and nebulae.\u003c\/li\u003e\n\u003cli\u003eFinding and framing before moving to a higher-power eyepiece.\u003c\/li\u003e\n\u003cli\u003eFaint galaxy and extended nebula observing, where a large exit pupil carries the surface brightness.\u003c\/li\u003e\n\u003cli\u003eWhole-disc lunar viewing at low magnification.\u003c\/li\u003e\n\u003cli\u003eDamp-climate and dew-heavy sites where a sealed eyepiece is worth the difference.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal directly.\u003c\/strong\u003e In a 2-inch focuser it goes in through a 2-inch to 1.25-inch adapter, which we stock.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 30. A 1200mm Dobsonian gives 40x; an 826mm refractor gives 27.5x; a 2000mm SCT gives 67x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 30 divided by the telescope's focal ratio. At f\/4.7 that is 6.4mm and at f\/10 it is 3mm — worth working out, because an exit pupil larger than your own dark-adapted pupil wastes some of the light the telescope collected.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e takes any standard 1.25-inch threaded filter on the 1.125-inches x 42 TPI thread. UHC and O-III filters are the usual pairing at this focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the series:\u003c\/strong\u003e the 52° Series shares an apparent field across focal lengths, so a set holds a consistent view as you change power.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 2x extender turns this into an effective 15mm while keeping the eye relief of the 30mm, which is a useful trick at this end of the range.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 52° field is a corrected field rather than a wide one.\u003c\/strong\u003e This series is built around edge sharpness and value. If immersion is the priority, the 68°, 82° and 100° Series cover that ground and we carry them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 27.2mm field stop is a 1.25-inch ceiling.\u003c\/strong\u003e A 2-inch eyepiece of the same focal length can pass a wider true field simply because the barrel is bigger. Within a 1.25-inch focuser, this is close to as wide as it gets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVery fast telescopes give a large exit pupil at 30mm.\u003c\/strong\u003e At f\/4.7 the exit pupil is 6.4mm, which some observers cannot fully use as their eyes age. A shorter focal length in the same series is the straightforward alternative, and we can suggest one for your telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof here means sealed against immersion, not built for use underwater.\u003c\/strong\u003e The 1 metre, 30 minute rating exists so that dew, rain and a drop into wet grass are non-events.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with the right adapter, though the design target is the eye.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 1.25-inch focuser or diagonal and is ready to use immediately. There is nothing to assemble, collimate or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 30. A 1000mm telescope gives 33x, a 1200mm gives 40x and a 2000mm gives 67x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow wide is the true field?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e57.3 multiplied by the 27.2mm field stop, divided by your telescope's focal length. In a 1200mm telescope that is about 1.3°, which is around two and a half full Moons across.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. 19.9mm of eye relief is generous for a 30mm eyepiece, and the flip-down silicone eyecup folds back to let spectacles sit close enough to take in the whole field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it take filters?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, any standard 1.25-inch threaded filter on the 1.125-inches x 42 TPI thread at the bottom of the barrel. Nebula filters are a natural match at this focal length.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow is it different from a Plössl at a similar price?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eFour elements in two groups with EMD coatings on every lens-to-air surface and blackened element edges, a 52° field against a Plössl's roughly 50°, nearly 20mm of eye relief where a 30mm Plössl has considerably less at the eye lens, and a sealed argon-purged body. The eye relief and the sealing are where the practical difference lives.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it work in my 2-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, through a 2-inch to 1.25-inch adapter. Many 2-inch diagonals include one, and we stock them if yours does not.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 204.1 gram, argon-purged 30mm eyepiece with a 52° field, a 27.2mm field stop that runs close to the 1.25-inch limit and 19.9mm of eye relief — the low-power, wide-field, comfortable end of a series built around edge correction and durability. If you would like help working out which focal lengths would round out your set for the telescope you own, send us its aperture and focal length and we will map it out with you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013466648687,"sku":"EPWP5230–01","price":138.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP5230-01_1_1663x__25015.jpg?v=1766553894"},{"product_id":"explore-scientific-40mm-52-series-waterproof-eyepiece","title":"Explore Scientific 52° Series 40mm Waterproof Eyepiece (2-Inch)","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 52° Series 40mm is the long focal length end of the 52° range: a 2.0″ O.D. double-taper barrel eyepiece with 27.1mm of eye relief, a 36.3mm field stop and four elements in two groups, edge blackened, behind EMD (Enhanced Multi-Layer Deposition) coatings on all lens-to-air surfaces. Published dimensions are 96,6mm long and 61.8mm wide, at 385.5 grams; 13.6 oz.\u003c\/p\u003e\n\u003cp\u003eAt 40mm this is a low-power, wide-true-field eyepiece. The 36.3mm field stop is the figure that matters: divided by the telescope's focal length and multiplied by 57.3, it gives the true field in degrees. In a 988mm refractor that is 2.11°; in a 1216mm apochromat, 1.71°; in a 1200mm SCT, 1.73°. Magnification follows from focal length divided by 40 — 25x, 30x and 30x respectively.\u003c\/p\u003e\n\u003cp\u003eThe housing is O-ring sealed and argon gas purged, tested under 1 meter of water for 30 minutes. Argon does not carry moisture the way trapped air does, so the internal surfaces stay clear of fogging as temperature drops through a night.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field deep-sky observers:\u003c\/strong\u003e 2.11° of true field in a 988mm refractor frames the Pleiades, the Double Cluster and the Veil in a way a shorter eyepiece cannot.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e 27.1mm of eye relief is enough to take in the whole 52° field with spectacles on, which is rare.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who use a finder eyepiece:\u003c\/strong\u003e at 25x to 30x in most telescopes, this is the eyepiece for locating a target before switching to power.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNebula filter users:\u003c\/strong\u003e the 2-inch thread takes an O-III or UHC filter, and low power with a large exit pupil is where those filters do their best work.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone observing in dew:\u003c\/strong\u003e the sealed, argon-purged body is built for damp nights.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e4 elements in 2 groups, edge blackened:\u003c\/strong\u003e a simple, low-element-count design, which keeps the number of air-to-glass surfaces down and transmission up — useful at low power where every photon is going into a large exit pupil.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e27.1mm eye relief:\u003c\/strong\u003e unusually generous, and the single most comfortable figure in the 52° Series.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e36.3mm field stop:\u003c\/strong\u003e a large true field for a 2-inch eyepiece, and the number to use for calculating field coverage.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2.0″ O.D. double-taper barrel:\u003c\/strong\u003e the taper resists the eyepiece sliding out of a diagonal if a thumbscrew loosens, which matters more with a 385.5 gram eyepiece than a light one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEMD coatings on all lens-to-air surfaces:\u003c\/strong\u003e raises transmission and holds contrast against scattered light.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eO-Ring sealed, argon gas purged,\u003c\/strong\u003e tested under 1 meter of water for 30 minutes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 2.0-inch filter thread (48mm x 0.75mm):\u003c\/strong\u003e takes 2-inch broadband, narrowband and lunar filters directly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemovable flip-down soft silicone rubber eyecup\u003c\/strong\u003e and slide-on caps top and bottom.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical glass, aluminum, steel and silicone rubber construction,\u003c\/strong\u003e laser engraved with focal length, series, serial number and brand.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLow-power sweeping through the Milky Way and large open clusters.\u003c\/li\u003e\n\u003cli\u003eExtended nebulae with a 2-inch narrowband filter fitted.\u003c\/li\u003e\n\u003cli\u003eFinding and framing targets before moving to a higher-power eyepiece.\u003c\/li\u003e\n\u003cli\u003eComet observing, where a large true field keeps head and tail together.\u003c\/li\u003e\n\u003cli\u003eFull-disc lunar viewing at low magnification.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocuser:\u003c\/strong\u003e the 2.0″ O.D. barrel fits any 2-inch focuser or diagonal directly. It does not fit a 1.25-inch focuser, and there is no adapter that makes a 2-inch eyepiece fit one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e standard 2.0-inch thread, 48mm x 0.75mm, which is the common astronomy filter standard.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 40. A 750mm Newtonian gives 19x; a 1216mm apochromat, 30x; a 2000mm SCT, 50x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field:\u003c\/strong\u003e 36.3 ÷ focal length × 57.3. A 750mm Newtonian yields 2.77°; a 2000mm SCT, 1.04°.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 40 ÷ focal ratio. An f\/10 SCT gives 4mm, an f\/8 apochromat 5mm, an f\/6.5 refractor 6.15mm and an f\/5 Newtonian 8mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 385.5 grams; 13.6 oz. On a small refractor or a Dobsonian this is enough to shift balance, so a counterweight or a retensioned altitude bearing is sometimes worth having.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil sets a practical limit at fast focal ratios.\u003c\/strong\u003e At f\/5 the 40mm produces an 8mm exit pupil, which is wider than most dark-adapted eyes accept, so part of the light is lost at the iris and a central obstruction can show as a shadow. Between f\/6 and f\/10 the eyepiece is in its element. If your telescope is faster than f\/6, a shorter focal length in the series holds the same field of view with a more usable exit pupil, and we can suggest one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 52° field is a corrected field rather than a wide one.\u003c\/strong\u003e Immersion is what the 68°, 82° and 100° Series are built for; the 52° Series concentrates on edge sharpness, eye relief and value.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt needs a 2-inch focuser or diagonal.\u003c\/strong\u003e At 2.0″ O.D. this eyepiece has no 1.25-inch path. Telescopes with 1.25-inch focusers are better served by the 1.25-inch focal lengths in the series, which we stock.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e385.5 grams sits at the heavy end for an eyepiece.\u003c\/strong\u003e In a small refractor's diagonal or a Dobsonian's focuser it changes the balance point, which is usually solved with a magnetic counterweight or a friction adjustment.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof means sealed against immersion, not built for use underwater.\u003c\/strong\u003e The 1 meter \/ 30 minute rating exists so that dew, rain and a drop into wet grass are non-events.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 2-inch focuser or diagonal and is ready to use. There is nothing to assemble, collimate or adjust, and the eyecup flips down for spectacle wearers.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 40. A 1000mm telescope gives 25x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much sky will it show?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide the 36.3mm field stop by your telescope's focal length and multiply by 57.3. A 1000mm telescope gives 2.08° of true field — about four times the width of the full Moon.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. 27.1mm of eye relief is more than most spectacle wearers need to take in the full 52° field, and the silicone eyecup folds down out of the way.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit my 1.25-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — the barrel is 2.0″ O.D. For a 1.25-inch focuser, the shorter 1.25-inch focal lengths in the 52° Series are the ones to look at, and we can point you to the closest equivalent.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it take filters?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, standard 2.0-inch threaded filters (48mm x 0.75mm) screw into the base of the barrel. Low power and a large exit pupil is exactly where an O-III or UHC filter shows its value on nebulae.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 40mm, 2-inch, argon-purged waterproof eyepiece with 27.1mm of eye relief, a 36.3mm field stop and a flat 52° field — the low-power, wide-true-field, spectacle-friendly end of the series, with a 2-inch filter thread for nebula work. If you would like us to work out the magnification, true field and exit pupil it will give in your particular telescope, send us the aperture and focal length and we will run the numbers.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013466681455,"sku":"EPWP5240–01","price":207.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP5240-01_3_1663x__68774.jpg?v=1766553900"},{"product_id":"explore-scientific-8-5mm-82-deg-series-ler-waterproof-eyepiece","title":"Explore Scientific 82° Series LER 8.5mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 82° Series LER 8.5mm is a high-magnification eyepiece with an ultra-wide 82° apparent field, built in a 1.25-inch barrel with long eye relief — which is what the LER in the name stands for. Explore Scientific lists 16.3mm of eye relief in its specification table for this eyepiece, and describes the design in its product text as offering roughly 15mm; both figures come from Explore Scientific and both are unusually generous for an 8.5mm focal length.\u003c\/p\u003e\n\u003cp\u003eThe eyepiece measures 106mm long and 50mm wide and weighs 9.9oz (280g). At 8.5mm it is squarely a high-power ocular: 97x in an 826mm refractor, 141x in a 1200mm Dobsonian, 235x in a 2000mm SCT. Combining that magnification with 82° of apparent field is the design's whole purpose, because at high power an ultra-wide field is what stops an object crossing the view in seconds.\u003c\/p\u003e\n\u003cp\u003eThe housing is O-ring sealed and argon-purged, giving a waterproof body that has no trapped humid air to fog from the inside as the temperature drops, and the optics are multi-coated for contrast at high magnification.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar and planetary observers:\u003c\/strong\u003e 8.5mm is a working high-power focal length across most apertures, and an 82° field means detail can be studied near the centre without constant renudging.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers observing at high power:\u003c\/strong\u003e eye relief is normally the first casualty at short focal lengths, and the LER design exists specifically to avoid that.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian owners:\u003c\/strong\u003e on an undriven mount, 82° of apparent field at 141x buys meaningfully more drift time than a 52° eyepiece at the same magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble-star observers\u003c\/strong\u003e who want magnification without a keyhole view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers at damp or dewy sites,\u003c\/strong\u003e where the argon-purged sealed housing keeps condensation on the outside where it can be dealt with.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e82° apparent field of view:\u003c\/strong\u003e the classic ultra-wide format, where the field edge sits outside the natural sweep of the eye and the view reads as a window rather than a tube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLong eye relief for an 8.5mm:\u003c\/strong\u003e 16.3mm on the Explore Scientific specification table, which is what makes an eyepiece this short usable with glasses.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ barrel:\u003c\/strong\u003e fits any standard 1.25-inch focuser or diagonal directly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eO-ring sealed, argon gas purged:\u003c\/strong\u003e a waterproof body with an inert fill, so internal fogging has nothing to condense from.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMulti-coated optics,\u003c\/strong\u003e specified by Explore Scientific for high-magnification observation of the planets, the Moon and deep-sky structure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished dimensions:\u003c\/strong\u003e 106mm long, 50mm wide, 9.9oz (280g) — light enough that a 1.25-inch focuser handles it without rebalancing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHigh-power lunar observing, where the wide field lets a whole crater chain stay in view.\u003c\/li\u003e\n\u003cli\u003ePlanetary detail on steady nights.\u003c\/li\u003e\n\u003cli\u003eSplitting double stars.\u003c\/li\u003e\n\u003cli\u003eCompact deep-sky targets — planetary nebulae, globular cluster cores, small galaxies.\u003c\/li\u003e\n\u003cli\u003eHigh-power observing on an undriven or manually nudged mount.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal.\u003c\/strong\u003e In a 2-inch focuser it goes in through a 2-inch to 1.25-inch adapter, which many 2-inch diagonals already include.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 8.5. An 826mm refractor gives 97x; a 1200mm Newtonian gives 141x; a 1500mm Maksutov gives 176x; a 2000mm SCT gives 235x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 8.5 divided by focal ratio — 1.8mm at f\/4.7 and 0.85mm at f\/10. Small exit pupils are normal at high power.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e pairing an 8.5mm with a 2x extender takes most apertures past the magnification the atmosphere will support on a typical night. A longer focal length is the better partner for an extender.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e standard 1.25-inch threaded filters are the usual pairing — a neutral density or variable polarising filter for the Moon, colour filters for planetary contrast.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e at 9.9oz it is a light eyepiece for an 82° design, so swapping it in rarely upsets a telescope's balance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e8.5mm is a high-power eyepiece, and the atmosphere governs it.\u003c\/strong\u003e On a steady night it will show what your aperture can resolve; on a turbulent one a longer focal length will show more. That is seeing, not optics, and a second longer eyepiece in the bag covers the difference.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific quotes eye relief two ways for this model\u003c\/strong\u003e — 16.3mm on the specification table and roughly 15mm in the product description. Both are Explore Scientific figures and both are reproduced here as published, and either way it is long for an 8.5mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo field stop diameter, element count or filter thread specification is published\u003c\/strong\u003e for this eyepiece, so those rows are absent from the table below rather than estimated. If one of them matters to your decision, ask and we will put the question to our Explore Scientific contact.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUltra-wide fields ask more of fast telescopes.\u003c\/strong\u003e At f\/4.7 the outer field of any 82° eyepiece works harder than it does at f\/10 — something to weigh if your telescope is a fast Newtonian, and something we can talk through against the alternatives we stock.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with the right adapter, though the design target is the eye.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 1.25-inch focuser or diagonal and is ready to use. There is nothing to assemble, collimate or adjust, and at 9.9oz it does not upset the balance of the telescope.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 8.5. A 1000mm telescope gives 118x and a 1200mm gives 141x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does LER mean?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eLong eye relief. Short focal length eyepieces normally place the eye very close to the top lens; this design holds it further back, which is what makes it comfortable and what makes observing with glasses on practical at 8.5mm.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I observe with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, and that is the point of the design. Explore Scientific publishes 16.3mm of eye relief on its specification table, which is long enough for spectacles at this focal length.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with the 100° Series?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 100° goes further on apparent field and is a considerably larger, heavier 2-inch eyepiece; the 82° LER is a light 1.25-inch design built around eye relief. If you tell us your telescope and what you observe, we will give you a straight comparison.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it take filters?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eStandard 1.25-inch threaded filters are the usual pairing. Explore Scientific does not publish the thread specification for this model, so if a particular filter is already in your case, send us the make and we will check it against the eyepiece first.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs 82° noticeable compared with 68°?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes — the field edge moves outside the eye's natural sweep, so instead of looking at a circle you are looking into a scene. At high power it also means considerably longer before an object drifts out on an undriven mount.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 280g, argon-purged 8.5mm eyepiece with an 82° apparent field, a 1.25-inch barrel and long eye relief on a focal length that usually has none — high magnification you can settle into rather than squint through. If you would like help pairing it with a longer focal length for nights when the seeing does not cooperate, send us your telescope's focal length and we will suggest one.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013647364207,"sku":"EPWP8285LE-01","price":207.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/82_85_1800x1800__57079.jpg?v=1766558569"},{"product_id":"explore-scientific-6-5mm-82-deg-series-ler-waterproof-eyepiece","title":"Explore Scientific 82° Series LER 6.5mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 82° Series LER 6.5mm is a high-magnification eyepiece built around one uncommon combination: an 82° apparent field and 16.8mm of eye relief in the same 1.25-inch body. Short focal lengths normally trade eye relief away first, and LER stands for the long eye relief that this design keeps instead.\u003c\/p\u003e\n\u003cp\u003eThe published figures are 6.5mm focal length, 16.8mm eye relief, a body 106mm long and 50mm wide, and a weight of 11.5oz (325g) in a 1.25-inch barrel. Explore Scientific specifies low-dispersion glass with multi-coated lenses in an argon-purged, O-ring sealed housing.\u003c\/p\u003e\n\u003cp\u003eAt 6.5mm this is firmly a high-power eyepiece. In a 663mm refractor it gives 102x; in a 1219mm Dobsonian, 188x; in a 2000mm Schmidt-Cassegrain, 308x. The 82° field is what makes that magnification comfortable rather than claustrophobic — an object at high power sits inside a wide surround instead of filling a tunnel.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar and planetary observers:\u003c\/strong\u003e 6.5mm is a working high-power focal length in most apertures, and low-dispersion glass is aimed at exactly the colour and contrast that fine planetary detail depends on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble-star observers\u003c\/strong\u003e who want magnification without a field so narrow the pair drifts out between looks.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers observing at high power:\u003c\/strong\u003e 16.8mm at 6.5mm focal length is the whole point of the LER designation, and it is unusual at this end of the range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian owners:\u003c\/strong\u003e an 82° field at high power buys real drift time on an undriven mount, where a narrow field would need nudging every few seconds.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers of compact deep-sky targets\u003c\/strong\u003e — planetary nebulae, globular cluster cores, small bright galaxies — where magnification darkens the sky background and pulls detail out.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e16.8mm eye relief at 6.5mm focal length:\u003c\/strong\u003e the defining specification of the LER line, and the reason this eyepiece is usable with glasses at magnifications where most designs are not.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e82° apparent field:\u003c\/strong\u003e ultra-wide, which at high power translates directly into how long an object stays in view and how much context surrounds it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow-dispersion glass with multi-coated lenses:\u003c\/strong\u003e low-dispersion elements bring wavelengths closer to a common focus inside the eyepiece, which shows as cleaner colour edges and better contrast on bright planetary detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eArgon purged and O-ring sealed:\u003c\/strong\u003e argon inside the housing does not condense the way trapped humid air does, so the internal surfaces stay clear as the temperature drops.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ barrel:\u003c\/strong\u003e fits any standard 1.25-inch focuser or diagonal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e106mm long and 50mm wide:\u003c\/strong\u003e a tall eyepiece for its barrel size, which is what an 82° field with 16.8mm of eye relief takes in glass.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e11.5oz (325g) published weight,\u003c\/strong\u003e substantial for a 1.25-inch eyepiece and worth knowing before it goes into a Dobsonian focuser.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHigh-power lunar observing — crater floors, rilles and the terminator.\u003c\/li\u003e\n\u003cli\u003ePlanetary detail on Jupiter, Saturn and Mars when the atmosphere is steady.\u003c\/li\u003e\n\u003cli\u003eSplitting close double stars.\u003c\/li\u003e\n\u003cli\u003eHigh-power observing on a manual altazimuth or Dobsonian mount, where the 82° field is what makes it practical.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal.\u003c\/strong\u003e In a 2-inch focuser it takes a 2-inch to 1.25-inch adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 6.5. A 663mm refractor gives 102x, a 1219mm Dobsonian 188x, a 1500mm Maksutov 231x, a 2000mm Schmidt-Cassegrain 308x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 6.5 ÷ the telescope's focal ratio. An f\/5.9 Dobsonian gives 1.1mm, an f\/6.5 refractor 1.0mm, an f\/10 Schmidt-Cassegrain 0.65mm. Small exit pupils are normal at high power and are what make the sky background go dark.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e takes standard 1.25-inch threaded filters. Colour and neutral-density filters are the usual companions for planetary and lunar work at this magnification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e 325g is heavy for a 1.25-inch eyepiece. On a Dobsonian or a small refractor, expect to recheck balance when swapping into it, and the same when swapping out.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocuser clearance:\u003c\/strong\u003e the body is 106mm long. In a short drawtube or a shallow eyepiece case, that dimension is worth checking against what you have.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e pairing an extender with a 6.5mm pushes past the useful magnification of most apertures. Longer focal lengths in the range are the better partner for an extender.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeeing conditions govern a 6.5mm eyepiece.\u003c\/strong\u003e On a steady night in a six-inch or larger telescope it will show what the aperture can resolve; on a turbulent night a longer focal length will show more. That is atmosphere rather than optics, and it is why most observers keep both.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish the field stop diameter, the element count or a coating specification\u003c\/strong\u003e for this eyepiece. Those rows read as not published below rather than being estimated. Without a field stop figure the true field cannot be calculated exactly, so we are not going to quote one — if it matters to you, we will ask our Explore Scientific representative.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not list the box contents\u003c\/strong\u003e for this model either, so we are not stating which caps or accessories are included. We can confirm that before it ships if you would like to know.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a heavy 1.25-inch eyepiece at 325g and 106mm long.\u003c\/strong\u003e Focusers with a light compression ring hold it fine, but balance on an undriven mount shifts noticeably when it goes in. A Dobsonian with adjustable tension handles that without fuss.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e16.8mm of eye relief means the eye sits further back than usual,\u003c\/strong\u003e which takes a session or two to get used to if you are coming from a short-relief planetary eyepiece. Once the eyecup height is set to suit you it holds.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 1.25-inch focuser or diagonal and works immediately. There is nothing to assemble or adjust beyond setting the eyecup where it suits your eye.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 6.5. A 1000mm telescope gives 154x; a 1219mm Dobsonian gives 188x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does LER mean here?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eLong eye relief. The published figure is 16.8mm, which at a 6.5mm focal length is unusual — short eyepieces normally place the eye very close to the lens. It is what makes high-power observing with glasses on, or simply for long stretches, comfortable.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. 16.8mm is enough for most spectacle wearers to take in the field, which is the specific problem this design sets out to solve.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs 6.5mm too much magnification for my telescope?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt depends on aperture and on the night. As a rule of thumb the atmosphere supports around twice the aperture in millimetres as a maximum useful magnification, so a 150mm telescope tops out near 300x on its best nights. At 6.5mm you reach 231x in a 1500mm telescope, which is inside that on a good night and beyond it on a poor one. Send us your telescope's aperture and focal length and we will tell you where this lands.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare to the 82° Series without LER?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe apparent field is the same 82°. What the LER design puts first is eye relief at short focal lengths, which is where the standard approach usually gives ground. If eye comfort at high power is what you are solving for, that is the difference.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 6.5mm high-power eyepiece with an 82° apparent field and 16.8mm of eye relief, in a 325g argon-purged 1.25-inch body with low-dispersion multi-coated glass — ultra-wide field and an unusually comfortable eye position at magnifications where both are normally hard to get. Tell us your telescope's focal length and we will confirm what power it gives you and how it sits alongside the eyepieces you already have.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013647396975,"sku":"EPWP8265LE-01","price":207.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/82_65_1800x1800__15675.jpg?v=1766558575"},{"product_id":"explore-scientific-4-5mm-82deg-series-ler-waterproof-eyepiece","title":"Explore Scientific 4.5mm 82deg Series LER Waterproof Eyepiece","description":"\u003cp data-open-accessibility-text-original=\"16px\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); margin-top: 1rem; margin-bottom: 1rem; color: rgb(76, 81, 84); font-family: \" libre franklin sans-serif rgb font-size:=\"\" background-color:=\"\"\u003eWith its particularly long eye relief of 15.9mm, the 4.5mm LER ocular from Explore Scientific’s 82° Series of Argon-Purged Waterproof Eyepieces puts the focus on a comfortable viewing experience for all observers. A long eye relief is especially important for eyeglass wearers because it allows them to enjoy the full field of view.\u003c\/p\u003e\u003cp data-open-accessibility-text-original=\"16px\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); margin-top: 1rem; margin-bottom: 1rem; color: rgb(76, 81, 84); font-family: \" libre franklin sans-serif rgb font-size:=\"\" background-color:=\"\"\u003eThe 4.5mm focal length is perfect for observing objects that would benefit from high magnifications such as the Moon, the planets and binary stars. When atmospheric conditions are almost perfect, this eyepiece can reveal planetary details that will are truly stunning. The 4.5mm size is also great for detailed examinations of the structures within deep sky objects like nebulae.\u003c\/p\u003e\u003cp data-open-accessibility-text-original=\"16px\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); margin-top: 1rem; margin-bottom: 1rem; color: rgb(76, 81, 84); font-family: \" libre franklin sans-serif rgb font-size:=\"\" background-color:=\"\"\u003eThis multi-element eyepiece achieves superior light transmission with edge-blackened optics made of low-dispersion glass with a high refractive index. Each lens also is fully multi-coated with durable enhanced multi-layer deposition (EMD) coatings. The combination of these factors maximizes the potential of your telescope to capture the celestial wonders you seek with sharp contrast, high resolution and crisp definition.\u003c\/p\u003e\u003cp data-open-accessibility-text-original=\"16px\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); margin-top: 1rem; margin-bottom: 1rem; color: rgb(76, 81, 84); font-family: \" libre franklin sans-serif rgb font-size:=\"\" background-color:=\"\"\u003eLike the others eyepieces in Explore Scientific 82° Series, this ocular has an ultra-wide 82° apparent field of view that immerses observers in the cosmos and naturally promotes relaxation at the eyepiece. When you relax your eyes and take in the scene presented before you, it is much easier to observe for longer periods of time, and details begin to materialize that were not revealed at first glance. The broad field of view promotes the use of averted vision, which involves looking slightly to the side of a target object rather than directly at it. This is especially helpful when observing faint objects, because using averted vision puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.\u003c\/p\u003e\u003cp data-open-accessibility-text-original=\"16px\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); margin-top: 1rem; margin-bottom: 1rem; color: rgb(76, 81, 84); font-family: \" libre franklin sans-serif rgb font-size:=\"\" background-color:=\"\"\u003eAll Explore Scientific Waterproof Eyepieces are gas-purged and O-ring sealed to create a waterproof environment that is impervious to internal fogging and prevents contaminants like fungus and dust from entering the ocular housing. This design makes cleaning the eyepiece a breeze.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013647528047,"sku":"EPWP8245LE-01","price":207.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/82_45_1800x1800__11504.jpg?v=1766558580"},{"product_id":"72-ed-series-6-5mm-waterproof-eyepiece","title":"Explore Scientific 72° ED Series 6.5mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 72° ED Series 6.5mm is a short focal length waterproof eyepiece with a 1.25-inch barrel, built around extra-low-dispersion glass. At 6.5mm it is a high-magnification eyepiece: in a 988mm refractor it gives 152x, in a 1500mm Maksutov 231x.\u003c\/p\u003e\n\u003cp\u003eThe 72° apparent field sits between the 68° Series and the 82° Series — wide enough that an object at high power stays in view noticeably longer than it would in a 52° eyepiece, without the outer-field demands of a 100° design.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar and planetary observers:\u003c\/strong\u003e 6.5mm is a working high-power focal length in most apertures, and ED glass is aimed squarely at the colour and contrast that planetary detail depends on.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble-star observers\u003c\/strong\u003e needing magnification without a field so narrow that the pair drifts out between looks.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUndriven and Dobsonian users:\u003c\/strong\u003e the wider apparent field buys drift time at high power on an unguided mount.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e Explore Scientific specifies generous eye relief for the series, which is the usual constraint at this focal length.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtra-low-dispersion (ED) glass:\u003c\/strong\u003e reduces chromatic aberration within the eyepiece itself, which shows as cleaner colour separation and higher contrast on planetary detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e72° apparent field of view:\u003c\/strong\u003e more immersive than the 52° and 62° Series, and easier on the outer field than the 82° and 100° designs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ barrel:\u003c\/strong\u003e fits any standard 1.25-inch focuser or diagonal directly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof construction,\u003c\/strong\u003e consistent with the sealed housings used across the Explore Scientific waterproof eyepiece range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGenerous eye relief\u003c\/strong\u003e for the focal length, which keeps extended sessions comfortable and makes observing with glasses on practical.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHigh-power lunar and planetary observing.\u003c\/li\u003e\n\u003cli\u003eSplitting double stars.\u003c\/li\u003e\n\u003cli\u003eCompact deep-sky targets — planetary nebulae and globular cluster cores.\u003c\/li\u003e\n\u003cli\u003eHigh-power observing on an undriven mount, where apparent field translates directly into time on target.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal.\u003c\/strong\u003e In a 2-inch focuser it needs a 2-inch to 1.25-inch adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 6.5. A 1200mm SCT gives 185x; a 750mm Newtonian gives 115x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e takes standard 1.25-inch threaded filters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the series:\u003c\/strong\u003e the 72° ED Series runs 6.5mm, 8.5mm, 11.5mm, 15mm, 20mm, 25mm, 30mm and 40mm, so a matched set holds the same apparent field and eye position across focal lengths.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e6.5mm is a high-power eyepiece, and seeing governs it.\u003c\/strong\u003e On a steady night in a 6-inch or larger telescope it will show what the aperture can do; on a turbulent night a longer focal length will show more. That is atmosphere, not optics.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not currently publish a full specification table for this series.\u003c\/strong\u003e Eye relief, field stop diameter, element count and weight are not given on their product page, so those rows are absent below rather than estimated. If you need a specific figure before ordering, ask us and we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with an adapter, but the design target is the eye.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 1.25-inch focuser or diagonal and is ready immediately. Nothing to assemble or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 6.5. A 1000mm telescope gives 154x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does the ED glass actually change?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExtra-low-dispersion glass brings wavelengths closer to a common focus inside the eyepiece, so colour edges on bright targets are cleaner and fine planetary contrast holds up better than in a standard-glass design of the same field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare to the 82° Series at the same focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 82° gives a wider, more immersive field; the 72° ED is built around glass type and eye relief instead. Which one suits you depends on whether you value field width or comfort and colour correction more — tell us what you observe and we will give you a straight answer.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExplore Scientific specifies generous eye relief for this series, which is what makes that practical. They do not publish the figure in millimetres, so we are not going to quote one — if it is the deciding factor for you, ask and we will confirm it with our rep first.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 6.5mm ED-glass eyepiece with a 72° field and a 1.25-inch barrel — high magnification with more field and more eye relief than a short-focal-length eyepiece usually offers. If you are filling out a focal-length set for a particular telescope, send us its aperture and focal length and we will map out which of the series make sense.\u003c\/p\u003e\n","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950319431791,"sku":"EPWP7265ED-01","price":415.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP7265ED-01.webp?v=1776180613"},{"product_id":"72-ed-series-8-5mm-waterproof-eyepiece","title":"Explore Scientific 72° ED Series 8.5mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 72° ED Series 8.5mm is a waterproof eyepiece with a 1.25-inch barrel, built around extra-low-dispersion glass and a 72-degree apparent field. Explore Scientific positions the series for planetary work and deep-sky objects alike, and specifies long eye relief as one of its design priorities.\u003c\/p\u003e\n\u003cp\u003e8.5mm is a high-power focal length in nearly any telescope. In a 714mm refractor it works at 84x, in a 1000mm instrument 118x, in a 1500mm Maksutov 176x. That range covers the magnifications where lunar and planetary detail lives without pushing straight into the territory that only exceptional seeing supports.\u003c\/p\u003e\n\u003cp\u003eThe 72° field sits between the 68° and 82° Series. It is wide enough that an object at high power stays in a hand-guided field noticeably longer, while keeping the eye position and outer-field correction less demanding than a 100° design.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary observers:\u003c\/strong\u003e ED glass targets exactly the colour error and contrast loss that fine planetary detail depends on, and 8.5mm reaches the magnification range where that detail appears.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e Explore Scientific specifies long eye relief for the series, and eye relief is normally the first casualty at short focal lengths.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven-mount users:\u003c\/strong\u003e a 72° apparent field converts directly into drift time, which is the practical currency of high-power observing without tracking.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble-star observers\u003c\/strong\u003e who want magnification without a field so tight that the pair leaves view between looks.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers filling a gap:\u003c\/strong\u003e 8.5mm falls between the more common 9mm and 8mm steps, which makes it useful for splitting the difference in an existing set.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtra-low-dispersion (ED) glass:\u003c\/strong\u003e reduces chromatic aberration generated inside the eyepiece itself, which shows as cleaner colour edges on bright targets and better-held contrast on subtle planetary shading.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e72° apparent field of view:\u003c\/strong\u003e more field than the 52° and 62° Series, less demanding at the edge than the 82° and 100° designs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLong eye relief\u003c\/strong\u003e specified for the series, which is what makes extended sessions and observing with glasses on practical at a short focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof construction,\u003c\/strong\u003e consistent with the sealed housings Explore Scientific uses across its waterproof eyepiece range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25-inch barrel\u003c\/strong\u003e fitting any standard focuser or diagonal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e8.5mm focal length,\u003c\/strong\u003e a step that sits between the usual 8mm and 9mm offerings.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHigh-power lunar observing, where ED glass keeps the limb clean.\u003c\/li\u003e\n\u003cli\u003ePlanetary detail on Jupiter, Saturn and Mars at magnifications the aperture supports.\u003c\/li\u003e\n\u003cli\u003eSplitting close double stars.\u003c\/li\u003e\n\u003cli\u003eCompact deep-sky targets — planetary nebulae, small galaxies and globular cluster cores.\u003c\/li\u003e\n\u003cli\u003eHigh-power observing on a hand-guided mount, where apparent field is what buys time on target.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal.\u003c\/strong\u003e In a 2-inch focuser it seats with a 2-inch to 1.25-inch adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 8.5. A 750mm Newtonian gives 88x, a 1200mm SCT gives 141x, a 2000mm SCT gives 235x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e takes standard 1.25-inch threaded filters, including lunar, colour and narrowband types.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 2x extender makes this an effective 4.25mm, which reaches magnifications that only steady nights and larger apertures support.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the series:\u003c\/strong\u003e the 72° ED Series spans several focal lengths, so a matched set holds the same apparent field and a consistent eye position from low power to high.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish a specification table for this eyepiece.\u003c\/strong\u003e Eye relief in millimetres, field stop diameter, element count, body dimensions and weight are all absent from their product page, so those rows read as not published below rather than carrying an estimate. If a specific figure decides the purchase for you, ask and we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e8.5mm is governed by the atmosphere as much as by the optics.\u003c\/strong\u003e On a steady night in a 6-inch or larger telescope it will show what the aperture can do; on a turbulent night a longer focal length shows more. That is seeing rather than glass.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrue field cannot be calculated precisely without a field stop figure.\u003c\/strong\u003e The 72° apparent field divided by the working magnification gives a close approximation — roughly 0.6° at 118x — and that is the honest way to estimate it here.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with the right adapter, though the design target is the eye rather than a sensor.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 1.25-inch focuser or diagonal and is ready to observe with straight away. Nothing to assemble, align or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 8.5. A 1000mm telescope gives 118x; a 1500mm gives 176x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does ED glass do in an eyepiece?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExtra-low-dispersion glass spreads wavelengths less than standard optical glass, so the eyepiece brings colours closer to a common focus. In practice that means cleaner edges on bright objects and fine planetary contrast that holds up better than in a conventional-glass design of the same field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I observe with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExplore Scientific specifies long eye relief for this series, which is what makes that practical. They do not publish the figure in millimetres, so no number is quoted here — if it is the deciding factor, ask and we will get it confirmed first.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare to the 82° Series at a similar focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 82° gives a wider, more immersive field; the 72° ED is built around glass type and eye comfort instead. Which one suits you comes down to whether field width or colour correction and eye relief matters more for what you observe — tell us and we will give you a straight comparison.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy 8.5mm rather than 8 or 9?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt is a deliberate half-step. In a set that already has a 6mm and an 11mm, 8.5mm lands neatly in between rather than duplicating a power you already own.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: an 8.5mm ED-glass eyepiece with a 72° apparent field, long eye relief and a 1.25-inch waterproof barrel — high magnification with more field and more eye comfort than short focal lengths usually allow. If you are working out how it fits alongside eyepieces you already own, send us the list and your telescope's focal length and we will show you where the gaps are.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950319464559,"sku":"EPWP7285ED-01","price":415.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP7285ED-01.webp?v=1776180692"},{"product_id":"72-ed-series-11-5mm-waterproof-eyepiece","title":"Explore Scientific 72° ED Series 11.5mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 72° ED Series 11.5mm is a waterproof eyepiece with a 1.25-inch barrel, built around extra-low-dispersion glass and a 72-degree apparent field. It carries item number EPWP72115ED-01.\u003c\/p\u003e\n\u003cp\u003eEleven and a half millimetres lands in an interesting place. It is not the shortest focal length in a set and not a general-purpose medium, but the step where a telescope starts working near its resolution limit while the exit pupil is still large enough to be forgiving. In a 1200mm Schmidt-Cassegrain it gives 104x; in a 1900mm Maksutov, 165x; in a 750mm Newtonian, 65x; in a 1000mm refractor, 87x. On most instruments that is the magnification you settle at once the target is found and the seeing has been assessed — high enough for planetary detail and globular cluster resolution, low enough that a moment of poor seeing does not end the view.\u003c\/p\u003e\n\u003cp\u003eThe exit pupil follows from the telescope's focal ratio: 11.5 divided by f\/6 gives 1.9mm, divided by f\/10 gives 1.15mm. Both are in the range where the eye's own aberrations stay out of the way and a faint galaxy still has enough surface brightness to register.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary observers:\u003c\/strong\u003e ED glass inside the eyepiece is aimed at exactly the colour errors that blur fine low-contrast detail on Jupiter and Mars.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble-star observers:\u003c\/strong\u003e 11.5mm produces working high power in most apertures while leaving enough field that a pair does not vanish between glances.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGlobular cluster observers:\u003c\/strong\u003e this is roughly where a cluster stops being a fuzzy ball and starts resolving into individual stars in a mid-aperture telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e Explore Scientific specify eye relief for this series as comfortable enough to observe with glasses on, which is unusual at a focal length this short.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven-mount users:\u003c\/strong\u003e 72 degrees of apparent field translates directly into more seconds on target between nudges at high magnification.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e11.5mm focal length:\u003c\/strong\u003e the high-power working step — 87x in a 1000mm telescope, 165x in a 1900mm one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtra-low-dispersion glass:\u003c\/strong\u003e ED elements inside the eyepiece reduce the eyepiece's own contribution to chromatic aberration, which shows up as cleaner edges on bright targets and better fine contrast.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e72° apparent field of view:\u003c\/strong\u003e substantially wider than a 52° or 62° design, and less demanding on eye placement than the 82° and 100° Series.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25-inch barrel:\u003c\/strong\u003e fits any standard 1.25-inch focuser or star diagonal directly, and a 2-inch focuser with an adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComfortable eye relief for the focal length:\u003c\/strong\u003e the property that usually gets sacrificed first as eyepiece focal length drops, and the one Explore Scientific calls out for this series.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof construction:\u003c\/strong\u003e a sealed housing, consistent with the waterproof eyepiece range Explore Scientific builds.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLunar detail along the terminator at working high power.\u003c\/li\u003e\n\u003cli\u003ePlanetary observing — belt structure on Jupiter, the Cassini division, Martian surface markings during a favourable opposition.\u003c\/li\u003e\n\u003cli\u003eSplitting double stars at magnifications where the pair is well separated but still bright.\u003c\/li\u003e\n\u003cli\u003eResolving globular clusters and picking out the central stars of planetary nebulae.\u003c\/li\u003e\n\u003cli\u003eHigh-power observing on an undriven mount, where apparent field is what buys observing time.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal.\u003c\/strong\u003e In a 2-inch focuser it needs a 2-inch to 1.25-inch adapter, which we stock.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length divided by 11.5. A 650mm refractor gives 57x, a 1500mm Maksutov gives 130x, a 2000mm SCT gives 174x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e the 1.25-inch barrel takes standard 1.25-inch threaded filters — neutral density and variable polarisers for the Moon, colour filters for planetary contrast, narrowband for nebulae.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 2x extender in front of this eyepiece produces an effective 5.75mm, which is past the useful magnification of smaller apertures. On a large instrument on a steady night it has its place; on most nights the eyepiece on its own is doing the right thing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGlasses:\u003c\/strong\u003e the series is specified for comfortable eye relief, and a fold-down eyecup is what lets a spectacle lens sit close enough to take in the whole field. Explore Scientific does not publish the eye relief in millimetres for this model, so we are not going to quote a figure — if it is your deciding factor, we will confirm it with our rep first.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeeing governs an 11.5mm eyepiece more than the optics do.\u003c\/strong\u003e On a steady night in a mid-aperture telescope it will show what the aperture is capable of; on a turbulent night a longer focal length shows more. That is the atmosphere, not the eyepiece, and it is the reason most observers own several focal lengths.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not publish a full specification table for this model.\u003c\/strong\u003e Eye relief in millimetres, field stop diameter, element count, coating specification and weight are absent from their page, so those rows are blank below rather than estimated. We are happy to put any of them to our Explore Scientific rep if you need the number before ordering.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e72 degrees is wide, and wide eyepieces reward good eye placement.\u003c\/strong\u003e Taking a moment to settle the eye at the right distance is what brings the field edge into view, and the fold-down eyecup is there to make that position repeatable.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece projection onto a camera is possible with an adapter, though the design intent is the observer's eye.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. It drops into any 1.25-inch focuser or diagonal and is ready to use immediately — nothing to assemble, nothing to adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 11.5. A 1000mm telescope gives 87x, a 1200mm gives 104x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat difference does the ED glass make?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExtra-low-dispersion glass bends the different wavelengths by more similar amounts than ordinary optical glass, so the eyepiece adds less colour error of its own on top of whatever the telescope delivers. In practice that reads as cleaner edges on the lunar limb and bright planets, and a little more of the fine contrast that planetary detail depends on.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with a 2-inch focuser?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, with a 2-inch to 1.25-inch adapter. Most 2-inch star diagonals include one.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with the 82° Series at a similar focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 82° Series gives a wider and more immersive field; the 72° ED Series is built around glass type and eye comfort instead. Which suits you depends on whether field width or colour correction and eye relief matters more for the observing you do — tell us what you look at most and we will give you an honest steer.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it work on a Dobsonian?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, and the 72-degree field is one of the reasons to choose it for one. At 11.5mm in a typical Dobsonian focal length the magnification is high, and the wider apparent field is what keeps the object in view longer between nudges.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: an 11.5mm ED-glass eyepiece with a 72-degree field and a 1.25-inch barrel, sealed against weather and specified with enough eye relief to work with glasses on — the high-power step that still leaves room to breathe. If you are filling out a focal-length set for a particular telescope, send us its aperture and focal length and we will map out which focal lengths would actually add something.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950319595631,"sku":"EPWP72115ED-01","price":415.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP72115ED-01.webp?v=1776180786"},{"product_id":"72-ed-series-15mm-waterproof-eyepiece","title":"Explore Scientific 72° ED Series 15mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 72° ED Series 15mm is a medium-focal-length waterproof eyepiece on a 1.25-inch barrel, built around extra-low-dispersion glass. It presents a 72° apparent field, and Explore Scientific specifies generous eye relief for the series as a design goal rather than an afterthought.\u003c\/p\u003e\n\u003cp\u003eAt 15mm it lands in the most-used part of a focal-length set. In a 952mm refractor it gives 63x; in a 1200mm Schmidt-Cassegrain, 80x; in a 1500mm Maksutov, 100x; in a 480mm short refractor, 32x. That is the range where most deep-sky observing happens — high enough to darken the background sky and pull out structure, low enough that the exit pupil stays comfortable and the object still has room to breathe.\u003c\/p\u003e\n\u003cp\u003eThe 72° field sits between the 68° Series and the 82° Series. It is wide enough that an object at medium power drifts across the field slowly on an undriven mount, without asking the outer field to perform the way a 100° design does.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers\u003c\/strong\u003e working clusters and nebulae, where 15mm is often the single most productive focal length in the case.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven-mount users:\u003c\/strong\u003e a wider apparent field converts directly into more seconds on target between nudges.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e Explore Scientific builds generous eye relief into this series, which is the usual sticking point once focal lengths drop below 20mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who want colour fidelity:\u003c\/strong\u003e the ED glass is there to keep colour edges clean on bright stars and to hold contrast on planetary detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone observing in dew or damp air:\u003c\/strong\u003e the waterproof housing is consistent with the sealed construction used across the Explore Scientific waterproof eyepiece range.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtra-low-dispersion (ED) glass:\u003c\/strong\u003e reduces chromatic aberration generated inside the eyepiece itself, which shows up as cleaner colour separation on bright stars and better-held contrast on fine detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e72° apparent field of view:\u003c\/strong\u003e a genuinely wide field that still keeps the outer zone well behaved, and one that suits both framing large objects and holding smaller ones in view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e15mm focal length:\u003c\/strong\u003e the workhorse power in most telescopes, and the one most observers reach for first on a deep-sky target.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ barrel:\u003c\/strong\u003e fits any standard 1.25-inch focuser or diagonal directly, with no adapter needed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof construction,\u003c\/strong\u003e in line with the sealed housings Explore Scientific uses across its waterproof eyepiece lines.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGenerous eye relief for the focal length,\u003c\/strong\u003e which keeps long sessions comfortable and makes observing with glasses on practical.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMedium-power deep-sky observing — open clusters, globular clusters, emission and reflection nebulae, and the brighter galaxies.\u003c\/li\u003e\n\u003cli\u003eLunar observing at moderate magnification, where the whole disc or a large region frames well.\u003c\/li\u003e\n\u003cli\u003eObserving on an undriven Dobsonian, where 72° of apparent field buys drift time.\u003c\/li\u003e\n\u003cli\u003eObserving with eyeglasses on, where the series' eye relief is the enabling factor.\u003c\/li\u003e\n\u003cli\u003eFilling the mid-power slot in a matched 72° ED set so the apparent field and eye position stay consistent as you change magnification.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal.\u003c\/strong\u003e In a 2-inch focuser it seats in a 2-inch to 1.25-inch adapter, which we stock.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 15. A 750mm Newtonian gives 50x; a 1000mm telescope 67x; a 2000mm SCT 133x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 15mm divided by your telescope's focal ratio. That is 2.5mm at f\/6 and 1.5mm at f\/10 — comfortable figures for extended deep-sky viewing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e takes standard 1.25-inch threaded filters. At 15mm a UHC or O-III filter is the classic pairing for emission nebulae, and a broadband filter helps from a light-polluted site.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 2x extender gives the magnification of a 7.5mm eyepiece while retaining the eye position and field character of the 15mm, which is a useful route to high power for eyeglass wearers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the series:\u003c\/strong\u003e the 72° ED Series spans several focal lengths, so a matched set holds the same apparent field and a similar eye position as you move through magnifications.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific does not currently publish a specification table for this eyepiece.\u003c\/strong\u003e Eye relief in millimetres, field stop diameter, element count, physical dimensions and weight are not given on their product page, so those rows appear below as unpublished rather than estimated. If you need a specific figure before ordering, ask us and we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithout a published field stop, we cannot calculate your true field precisely.\u003c\/strong\u003e A reasonable working estimate comes from apparent field divided by magnification, but that is an approximation rather than a specification, so we leave the row blank rather than fill it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with the right adapter, but the design target here is the eye.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e72° is wide, and wide fields ask for good eye placement.\u003c\/strong\u003e Taking in the whole field means holding your eye in the right position rather than pressing it to the lens — a habit that comes quickly and pays off across every wide-field eyepiece you own.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eED glass addresses colour generated inside the eyepiece,\u003c\/strong\u003e not colour produced by your telescope's objective. In a fast achromatic refractor, the objective remains the dominant source of any fringing you see, and a minus-violet filter is the tool for that end of the problem.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 1.25-inch focuser or diagonal and is ready immediately. Nothing to assemble, collimate or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 15. A 1200mm telescope gives 80x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does the ED glass actually change?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExtra-low-dispersion glass brings different wavelengths closer to a common focus inside the eyepiece, so colour edges around bright stars are cleaner and fine low-contrast detail holds up better than it does in a standard-glass design of the same field width.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with glasses on?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExplore Scientific specifies generous eye relief for this series, which is what makes that practical. They do not publish the figure in millimetres, so we would rather not quote one — if it is the deciding factor, ask and we will confirm it with our rep first.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow wide a true field does it give?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThat depends on the field stop diameter, which Explore Scientific does not publish for this eyepiece. Dividing the 72° apparent field by your magnification gives a close working figure, and we can get the exact number from our rep if you need it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare with the 82° Series at the same focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 82° gives a wider, more immersive field; the 72° ED is built around glass type and eye relief instead, in a lighter and more compact body. Which suits you depends on whether field width or comfort and colour correction matters more in your observing — tell us how you observe and we will give you an honest answer.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it suitable for a Dobsonian?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eVery much so. The wider apparent field is exactly what an undriven mount benefits from, since an object at 72° takes noticeably longer to cross the field than it would in a narrow-field eyepiece at the same magnification.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 15mm ED-glass eyepiece with a 72° field, a 1.25-inch barrel and waterproof construction — the most-used magnification in most telescopes, with more field and more eye relief than the focal length usually brings. If you are building out a focal-length set for a particular telescope, send us its aperture and focal length and we will work out which of the series make sense together.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950319825007,"sku":"EPWP7215ED-01","price":415.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP7215ED-01.webp?v=1776180866"},{"product_id":"72-ed-series-20mm-waterproof-eyepiece","title":"Explore Scientific 72° ED Series 20mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 72° ED Series 20mm is a low-to-mid power waterproof eyepiece with a 1.25-inch barrel, built around extra-low-dispersion glass. Explore Scientific specifies a 72° apparent field of view and describes the optical design as using ED glass to reduce chromatic aberration, raise contrast and sharpen both planetary and deep-sky views, with comfortable eye relief for long sessions.\u003c\/p\u003e\n\u003cp\u003eAt 20mm this is the focal length most observers reach for as a working general-purpose eyepiece: in a 714mm refractor it gives 36x, in a 1200mm SCT 60x, in a 1500mm Dobsonian 75x. It is low enough to frame a cluster, high enough to start pulling structure out of a nebula, and it sits comfortably between a finder-like sweeping eyepiece and the high-power end of a set.\u003c\/p\u003e\n\u003cp\u003eThe 72° apparent field sits between the 68° Series and the 82° Series. It is wide enough that the field edge stops feeling like a tunnel, without the demands a 100° design places on the outer field or on the size and weight of the housing.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers\u003c\/strong\u003e who want a wide, contrasty mid-power view for open clusters, brighter galaxies and the large nebulae.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian and undriven mount users:\u003c\/strong\u003e a 72° field at 20mm gives real drift time before an object needs nudging back to centre.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who prefer a single go-to focal length\u003c\/strong\u003e that covers most of a night's targets without constant eyepiece changes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyeglass wearers:\u003c\/strong\u003e Explore Scientific specifies comfortable eye relief for the series, which is what makes observing with spectacles practical.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers building a matched 72° ED set\u003c\/strong\u003e so apparent field and eye position stay consistent from one focal length to the next.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone who observes in dew or damp air:\u003c\/strong\u003e the waterproof housing is built for it.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtra-low-dispersion (ED) glass:\u003c\/strong\u003e reduces chromatic aberration generated inside the eyepiece itself, which shows up as cleaner colour edges on bright stars and better contrast on subtle detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e72° apparent field of view:\u003c\/strong\u003e more open than the 52° and 62° Series, and less demanding on the outer field than the 82° and 100° designs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e20mm focal length:\u003c\/strong\u003e the mid-range workhorse position in most eyepiece sets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25″ barrel:\u003c\/strong\u003e fits any standard 1.25-inch focuser or diagonal directly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof construction,\u003c\/strong\u003e consistent with the sealed housings used across the Explore Scientific waterproof eyepiece range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComfortable eye relief\u003c\/strong\u003e specified for the series, which is what keeps a long session from becoming a squint.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eGeneral deep-sky observing — open clusters, brighter galaxies, large nebulae.\u003c\/li\u003e\n\u003cli\u003eFraming and locating targets before switching to a shorter focal length.\u003c\/li\u003e\n\u003cli\u003eWide low-power lunar views showing the whole disc with room around it.\u003c\/li\u003e\n\u003cli\u003eObserving on an undriven mount, where apparent field translates directly into time on target.\u003c\/li\u003e\n\u003cli\u003eOutreach and shared sessions, where a wide field makes it easier for a newcomer at the eyepiece to see what they are meant to be looking at.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits any 1.25-inch focuser or diagonal.\u003c\/strong\u003e In a 2-inch focuser it takes a 2-inch to 1.25-inch adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 20. A 952mm refractor gives 48x; a 1900mm Maksutov gives 95x; a 750mm Newtonian gives 38x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 20mm ÷ the telescope's focal ratio — 4mm at f\/5, 2mm at f\/10. A 4mm exit pupil is a comfortable dark-site figure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal extenders:\u003c\/strong\u003e a 20mm eyepiece behind a 2x extender behaves like a 10mm while keeping the eye relief of the longer eyepiece, which is a useful trick for spectacle wearers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithin the series:\u003c\/strong\u003e the 72° ED Series covers a range of focal lengths, so a matched set holds the same apparent field and eye position throughout.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e Explore Scientific does not publish the filter thread specification for this model, so we are not quoting one. If you intend to run a UHC or O-III filter, ask and we will confirm the thread with our rep first.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific has not published a full specification table for this eyepiece.\u003c\/strong\u003e Eye relief in millimetres, field stop diameter, element count, coatings, physical dimensions and weight are all absent from their product page, so those rows read \"Not published by vendor\" below rather than carrying an estimate. If you need a specific figure before ordering, ask us and we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithout a published field stop diameter, true field cannot be calculated exactly.\u003c\/strong\u003e The 72° apparent field divided by the magnification gives a close approximation, and that is the honest way to work it out until the figure is published.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis is a recently listed product.\u003c\/strong\u003e Explore Scientific has not yet published a barcode or shipping weight for it, which is normal for a new addition to a series and tends to fill in over time.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with an adapter, but the design target is the eye.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIn a fast telescope, a 20mm eyepiece produces a large exit pupil.\u003c\/strong\u003e At f\/4 that is 5mm, which suits a dark site and shows sky glow under city lights. A narrowband filter or a shorter focal length is the usual remedy, and we stock both.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it drops into any 1.25-inch focuser or diagonal and is ready immediately. There is nothing to assemble or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 20. A 1000mm telescope gives 50x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does the ED glass change?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExtra-low-dispersion glass brings the different wavelengths closer to a common focus inside the eyepiece, so colour edges on bright stars are cleaner and fine contrast holds up better than a standard-glass design of the same field would manage.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does it compare to the 82° Series at a similar focal length?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 82° gives a wider, more immersive field; the 72° ED is built around glass type and eye relief instead. Which suits you depends on whether field width or comfort and colour correction matters more — tell us what you observe and we will give you a straight answer.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much eye relief does it have?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExplore Scientific describes it as comfortable for extended observing but does not publish the figure in millimetres, so we are not going to quote one. If it is the deciding factor, ask and we will confirm it with our rep first.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it a good match for a Dobsonian?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. At 20mm with a 72° field it gives a wide, easy view on an undriven mount, and objects take noticeably longer to drift out than they would in a narrower eyepiece.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use it with a focal extender?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes — a 2x extender turns it into the equivalent of a 10mm while preserving the longer eyepiece's eye relief, which many observers prefer to a native 10mm.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 20mm ED-glass eyepiece with a 72° apparent field in a waterproof 1.25-inch barrel — the mid-range focal length most nights get built around, with a wider field and better colour correction than a standard-glass design of the same size. If you are filling out a set for a particular telescope, send us its aperture and focal length and we will map out which focal lengths make sense alongside it.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950321266799,"sku":"EPWP7220ED-01","price":415.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP7220ED-01.webp?v=1776181164"},{"product_id":"72-ed-series-25mm-waterproof-eyepiece","title":"72° ED Series 25mm Waterproof Eyepiece","description":"\u003cp\u003eThe Explore Scientific 72 degree ED 25mm eyepiece with a 2 inch barrel is designed for expansive, low power viewing that reveals the broader structure of the night sky. It is ideal for observing large deep sky objects and sweeping rich star fields. The wider 2 inch format allows for a larger field stop, enhancing the 72 degree apparent field of view and creating a more immersive experience. This makes it easier to frame large objects and enjoy them in full context.\u003c\/p\u003e\n\u003cp\u003eExtra low dispersion glass ensures that image quality remains sharp and well corrected across the field. Color fringing is minimized, and contrast is enhanced, resulting in a cleaner and more natural view. The generous eye relief allows for comfortable viewing, even during extended sessions.\u003c\/p\u003e\n\u003cp\u003eThis eyepiece is a strong choice for those who want to maximize field of view and brightness while maintaining excellent image quality.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950321496175,"sku":"EPWP7225ED-01","price":484.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP7225ED-01.webp?v=1776181258"},{"product_id":"72-ed-series-30mm-waterproof-eyepiece","title":"72° ED Series 30mm Waterproof Eyepiece","description":"\u003cp\u003eThe Explore Scientific 72 degree ED 30mm eyepiece with a 2 inch barrel is built for ultra wide, low magnification viewing that allows you to fully immerse yourself in the night sky. It is particularly well suited for observing large nebulae, open clusters, and sweeping star fields. The 2 inch barrel design enhances the field of view, allowing for a broader and more expansive perspective. Combined with the 72 degree apparent field of view, this creates a truly immersive viewing experience.\u003c\/p\u003e\n\u003cp\u003eThe extra low dispersion glass maintains image quality across the field by reducing chromatic aberration and improving contrast. This ensures that even at lower magnifications, the view remains sharp and well defined. The eyepiece is designed for comfort, with long eye relief that supports extended observation.\u003c\/p\u003e\n\u003cp\u003eThis focal length is ideal for those who want to explore the sky at a wider scale and appreciate the full structure of large celestial objects.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950323396719,"sku":"EPWP7230ED-01","price":553.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP7230ED-01.webp?v=1776181299"},{"product_id":"72-ed-series-40mm-waterproof-eyepiece","title":"72° ED Series 40mm Waterproof Eyepiece","description":"\u003cp\u003ethe series, making it ideal for sweeping the night sky and observing the largest celestial objects. With its 2 inch barrel and expansive 72 degree apparent field of view, this eyepiece provides a truly immersive perspective. It allows you to take in entire star fields and large deep sky objects in a single view.\u003c\/p\u003e\n\u003cp\u003eThe extra low dispersion glass ensures that image quality remains sharp and well corrected, with reduced color fringing and improved contrast. This results in a clean and natural viewing experience even at very low magnification. The comfortable eye relief supports long, relaxed observing sessions.\u003c\/p\u003e\n\u003cp\u003eThis eyepiece is the ultimate wide field option for those who want to experience the full scale of the night sky.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950333227119,"sku":"EPWP7240ED-01","price":623.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP7240ED-01.webp?v=1776181411"},{"product_id":"92-ed-series-9mm-waterproof-eyepiece","title":"92° ED Series 9mm Waterproof Eyepiece","description":"\u003cp\u003eThe Explore Scientific 92 degree ED 9mm eyepiece with a 2 inch barrel is designed for high magnification viewing with an ultra wide, immersive field of view. It is ideal for observing planetary detail and smaller deep sky objects while maintaining a sense of space and scale. The 92 degree apparent field of view creates a dramatic, immersive experience that allows objects to remain in view longer and reduces the need for constant repositioning. This is especially valuable at higher magnifications.\u003c\/p\u003e\n\u003cp\u003eThe extra low dispersion glass enhances clarity by reducing chromatic aberration and improving contrast. Fine details become more visible, and color accuracy is preserved, resulting in a more refined image. The eyepiece also offers long eye relief, providing comfort during extended viewing sessions.\u003c\/p\u003e\n\u003cp\u003eThis is a premium option for those who want high magnification performance without sacrificing field of view.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950346989679,"sku":"EPWP9209ED-01","price":623.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP9209ED-01.webp?v=1776181604"},{"product_id":"92-ed-series-14mm-waterproof-eyepiece-coming-soon","title":"92° ED Series 14mm Waterproof Eyepiece","description":"\u003cp\u003eThe Explore Scientific 92 degree ED 14mm eyepiece with a 2 inch barrel offers a powerful combination of moderate magnification and an ultra wide field of view. It is well suited for a wide range of observing targets, from planetary detail to deep sky exploration. The 92 degree apparent field of view creates a highly immersive experience, allowing users to take in more of the sky at once while maintaining focus on their target. This enhances both usability and overall enjoyment.\u003c\/p\u003e\n\u003cp\u003eExtra low dispersion glass improves image quality by reducing color fringing and increasing contrast. This results in sharper, more detailed views with accurate color representation. The long eye relief ensures comfortable viewing, even during extended sessions.\u003c\/p\u003e\n\u003cp\u003eThis focal length provides excellent versatility and is a strong all around performer within the 92 degree series.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950350921839,"sku":"EPWP9214ED-01","price":623.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP9214ED-01.webp?v=1776181675"},{"product_id":"92-ed-series-20mm-waterproof-eyepiece","title":"92° ED Series 20mm Waterproof Eyepiece","description":"\u003cp\u003eThe Explore Scientific 92 degree ED 20mm eyepiece with a 2 inch barrel is designed for immersive, wide field viewing with a balance of brightness and magnification. It is particularly effective for observing deep sky objects while maintaining an expansive perspective. The ultra wide 92 degree apparent field of view creates a panoramic experience that enhances the sense of depth and scale. Objects remain in view longer, making observation more fluid and engaging.\u003c\/p\u003e\n\u003cp\u003eThe extra low dispersion glass ensures that image quality remains sharp and well corrected. Color fringing is minimized, and contrast is enhanced, resulting in a clean and detailed image. The eyepiece is built for comfort, with long eye relief that supports extended observation.\u003c\/p\u003e\n\u003cp\u003eThis focal length is ideal for those who want a wide field experience while still maintaining enough magnification to reveal structure and detail.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950357639279,"sku":"EPWP9220ED-01","price":623.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP9220ED-01.webp?v=1776181778"},{"product_id":"92-ed-series-25mm-waterproof-eyepiece","title":"Explore Scientific 92° ED Series 25mm Waterproof Eyepiece","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Explore Scientific 92° ED Series 25mm is the widest-field end of Explore Scientific's eyepiece line: a 2-inch barrel ocular with a 92° apparent field, built around extra-low-dispersion glass. At 25mm it is a low-power, wide-field eyepiece, which is the combination that produces the enveloping views large deep-sky objects reward.\u003c\/p\u003e\n\u003cp\u003e92° is past the point where the field edge sits inside your peripheral vision. In practice the boundary of the view stops registering as a circle and starts behaving like a window, and objects are seen in a surrounding star field rather than isolated in the middle of a dark disc. That effect is the entire design goal of the series, and it is why a 2-inch barrel is necessary — a field this wide at 25mm needs a field stop far larger than a 1.25-inch barrel can pass.\u003c\/p\u003e\n\u003cp\u003eExplore Scientific specifies extra-low-dispersion glass to control colour across that very wide field, extended eye relief for comfort, and waterproof construction. This is a sparsely documented product on the vendor side, and what follows works only from what Explore Scientific actually publishes.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky observers with a 2-inch focuser\u003c\/strong\u003e who want the widest, most immersive low-power view available in the range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers of large extended objects\u003c\/strong\u003e — the Veil, the Andromeda halo, the North America Nebula, large open clusters — that overflow a narrower field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDobsonian owners:\u003c\/strong\u003e a 92° field on an undriven mount is a long interval between nudges, and at 25mm the drift is slow to start with.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who value the surrounding star field\u003c\/strong\u003e as part of what they are looking at, rather than treating the target in isolation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone already invested in 2-inch eyepieces\u003c\/strong\u003e looking for the widest field in the line to sit at the low-power end of the set.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e92° apparent field of view:\u003c\/strong\u003e the widest in the Explore Scientific range, and wide enough that the field edge falls outside the eye's central attention.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtra-low-dispersion (ED) glass:\u003c\/strong\u003e reduces chromatic aberration generated inside the eyepiece itself. In a field this wide, colour control at the outer zones is one of the harder problems to solve, and ED elements are the standard answer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2-inch barrel:\u003c\/strong\u003e the format that allows a field stop large enough for 92° at 25mm. It fits any 2-inch focuser or 2-inch diagonal directly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e25mm focal length:\u003c\/strong\u003e low power in most telescopes, which is what makes the very wide apparent field translate into a very wide piece of sky.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtended eye relief,\u003c\/strong\u003e specified by Explore Scientific for the series, which is what makes it possible to take in the whole 92° without pressing against the eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof construction,\u003c\/strong\u003e consistent with the sealed housings Explore Scientific uses across its waterproof eyepiece range.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLow-power deep-sky observing of large nebulae, open clusters and extended galaxies.\u003c\/li\u003e\n\u003cli\u003eWide-field sweeping through the summer and winter Milky Way.\u003c\/li\u003e\n\u003cli\u003eFraming objects that are physically large on the sky — supernova remnants, the Hyades, the Pleiades, the Double Cluster.\u003c\/li\u003e\n\u003cli\u003eObserving on a Dobsonian or another undriven mount, where apparent field is time on target.\u003c\/li\u003e\n\u003cli\u003eNebula-filter observing, where a wide field and a low power make faint extended structure easiest to see.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocuser:\u003c\/strong\u003e a 2-inch focuser or a 2-inch diagonal is needed. A 1.25-inch focuser will not accept this eyepiece, and no adapter converts downward in that direction — if your telescope is 1.25-inch only, the widest true field available comes from a 1.25-inch design with a maximum-diameter field stop, and we can point you at one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnification:\u003c\/strong\u003e telescope focal length ÷ 25. A 663mm refractor gives 27x, a 1219mm Dobsonian 49x, a 2000mm Schmidt-Cassegrain 80x.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExit pupil:\u003c\/strong\u003e 25 ÷ the telescope's focal ratio. An f\/5.9 Dobsonian gives 4.2mm, an f\/6.5 refractor 3.8mm, an f\/10 Schmidt-Cassegrain 2.5mm. Below about f\/5 the exit pupil starts to exceed what many adult eyes dilate to.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e 2-inch eyepieces normally take 2-inch threaded filters, and a broadband or narrowband nebula filter is the natural partner for a wide low-power field. Explore Scientific does not publish the filter thread specification for this model, so we would rather check it than assume — ask us and we will confirm before you order.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBalance:\u003c\/strong\u003e 2-inch ultra-wide eyepieces are typically the heaviest items in a case. Explore Scientific publishes no weight for this one, so we are not quoting a figure; on a Dobsonian it is sensible to have some balance adjustment available when swapping into a 2-inch eyepiece.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific publishes no specification table for this eyepiece.\u003c\/strong\u003e Eye relief in millimetres, field stop diameter, element and group count, weight and physical dimensions are not given on their product page, so those rows are absent from the table below rather than estimated. If one of them decides the purchase for you, ask and we will put the question to our Explore Scientific representative before you commit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWithout a published field stop figure, the true field cannot be calculated exactly.\u003c\/strong\u003e We are not going to quote a number we cannot source. The magnification arithmetic above is exact; the true field is the one figure that has to wait on Explore Scientific.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA 2-inch focuser is a requirement, not a preference.\u003c\/strong\u003e This is the one compatibility point worth settling first — send us your telescope model and we will confirm the focuser size with you.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUltra-wide fields ask more of a telescope's focal ratio.\u003c\/strong\u003e In fast telescopes the outer field of any very wide eyepiece works hardest, which is part of why ED glass is in the design. In slower telescopes it is an easier job.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a visual eyepiece.\u003c\/strong\u003e Eyepiece-projection imaging is possible with the right adapter, but the design target is the eye.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — it slides into any 2-inch focuser or 2-inch diagonal and is ready to use. There is nothing to assemble, collimate or adjust.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat magnification will I get?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDivide your telescope's focal length in millimetres by 25. A 1000mm telescope gives 40x; a 1219mm Dobsonian gives 49x.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does 92° actually look like?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eWide enough that the edge of the field sits at the boundary of where your eye naturally looks. Rather than seeing a bright circle surrounded by black, you see a field of stars that keeps going as your eye moves across it. On large clusters and nebulae that changes the character of the view rather than just the size of it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit my telescope?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt needs a 2-inch focuser or a 2-inch diagonal. Most larger Dobsonians and most refractors with a 2-inch focuser take it directly. If you are not sure what your telescope has, send us the model and we will check.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does the ED glass change?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExtra-low-dispersion glass brings different wavelengths closer to a common focus inside the eyepiece, so colour edges on bright stars stay cleaner across the field. In a 92° design the outer field is where that work shows, because the light is bent hardest there.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow heavy is it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExplore Scientific does not publish a weight for this model, so we are not going to quote one. As a class, 2-inch ultra-wide eyepieces are on the heavy side. If the exact figure matters for balancing a mount, ask us and we will get it confirmed.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 25mm ED-glass eyepiece with a 92° apparent field in a 2-inch waterproof barrel — the widest, most enveloping low-power view in the Explore Scientific range, aimed squarely at large deep-sky objects. Explore Scientific publishes little beyond that, so if there is a figure you need before ordering, tell us which one and we will get it from them for you.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52950365372527,"sku":"EPWP9225ED-01","price":692.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/EPWP9225ED-01.webp?v=1776181861"}],"url":"https:\/\/ontariotelescope.com\/collections\/explore-scientific-eyepieces.oembed?page=3","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}