{"title":"Explore Scientific Plössl \u0026 Ortho Eyepieces","description":"\u003cp\u003eExplore Scientific Plössl and orthoscopic eyepieces — standard-field designs for planetary and double-star work. Goods ship factory-sealed. If you're unsure what fits your setup, ask us before you order and we'll confirm it.\u003c\/p\u003e","products":[{"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"}],"url":"https:\/\/ontariotelescope.com\/collections\/explore-scientific-plossl.oembed","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}