Explore Scientific 82° Series 14mm Waterproof Eyepiece

Product Overview

The Explore Scientific 82° Series 14mm is an argon-purged waterproof eyepiece on a 1.25-inch barrel, with a published 18.9mm field stop and 15.6mm of eye relief. At 83mm long, 48mm wide and 9.0 oz (256 g) it is unusually compact for an 82-degree design — most eyepieces of this apparent field at longer focal lengths need a 2-inch barrel and three times the weight.

14mm is the medium-power focal length in most telescopes: 71x in a 1000mm instrument, 86x in a 1200mm SCT, 34x in a 480mm refractor. Paired with an 82° apparent field, that combination gives a true field of 1.08° at 1000mm — the 18.9mm field stop divided by focal length, times 57.3 — which is roughly two lunar diameters across at 71x.

The optical design uses low-dispersion glass and high refractive index elements under enhanced multilayer coatings. Internal barrel surfaces are flat black and the lens edges are blackened, both aimed at keeping stray light out of a wide field where there is more of it to control.

Who It's For

• Observers who want a wide field in a 1.25-inch focuser: at 256 g and 83mm long, this delivers 82 degrees without needing a 2-inch focuser or a rebalance.
• Dobsonian and undriven mount users: an 82° field at medium power buys real drift time before the object leaves the view.
• Deep-sky observers working on globular clusters, brighter galaxies and planetary nebulae, where 14mm sits at a useful compromise between image scale and field.
• Travellers and portable-setup owners: 9.0 oz in a small case adds an 82° field to a lightweight kit.
• Observers in dew-heavy conditions: the argon-purged, sealed body is built for damp nights.

Key Features & Design

• 82° apparent field of view in a 1.25-inch barrel — the wide-field format without the 2-inch focuser requirement.
• 18.9mm field stop: the published figure that determines your true field. Divide by telescope focal length and multiply by 57.3 for degrees.
• 15.6mm eye relief, which at 14mm leaves room to observe without pressing your eye against the lens.
• Low-dispersion glass and high refractive index elements under enhanced multilayer coatings, aimed at contrast, resolution and a flat field.
• Flat black internal barrel surfaces and blackened lens edges, which is how scatter is controlled in a design with a lot of glass and a wide field.
• Argon purged and waterproof: dry inert gas inside a sealed housing, so internal fogging is not part of a long session.
• Compact and light: 83mm long, 48mm wide, 9.0 oz (256 g).

Recommended Uses

• Medium-power deep-sky observing — globular clusters, galaxies, planetary nebulae.
• Lunar observing, where 82 degrees puts the whole disc in a wide frame at moderate power.
• Open clusters that need both resolution and surrounding field.
• Observing on an undriven mount, where apparent field converts directly into time on target.
• Portable and travel setups built around a 1.25-inch focuser.

Compatibility and Accessory Notes

• Fits any 1.25-inch focuser or diagonal directly, and a 2-inch focuser with a 2-inch to 1.25-inch adapter.
• Magnification: telescope focal length divided by 14. A 1400mm Maksutov gives 100x; a 750mm Newtonian gives 54x.
• True field: 18.9 divided by focal length, times 57.3. A 1200mm SCT gives 0.90°; a 480mm refractor gives 2.26°.
• Exit pupil: 14 divided by focal ratio — 2.3mm at f/6, 1.4mm at f/10. Comfortable figures in both cases.
• Filters: standard 1.25-inch threaded filters thread into the barrel. Narrowband and oxygen-III filters pair well with this focal length on nebulae.
• Within the series: the 82° Series is parfocal, so a matched set holds the same focus position and eye placement as you change powers.

Good to Know Before You Order

• An 82° field asks something of the observer. Taking in the whole view means moving your eye slightly rather than staring straight ahead, which is normal for wide-field designs and takes a session or two to become second nature.
• Explore Scientific does not publish an element count for this eyepiece, so that row reads as unpublished below rather than being estimated. If it is a figure you want before ordering, ask and we will put it to our Explore Scientific rep.
• Eye placement is more particular than in a narrow-field eyepiece. 15.6mm of eye relief gives room to work with, and the fold-down eyecup sets a repeatable distance once you find it.
• A 1.25-inch barrel caps the true field. At 14mm and an 18.9mm field stop that cap is not in play — but if a still wider true field is what you are after, that means a longer focal length in a 2-inch format, and we stock those.
• It is a visual eyepiece. Projection imaging is possible with an adapter, though the design target here is the eye.

Frequently Asked Questions

Is it difficult to set up?

No — it drops into any 1.25-inch focuser or diagonal and is ready to observe with. At 256 g it changes nothing about your telescope's balance, so there is nothing to adjust afterwards either.

What magnification will I get?

Divide your telescope's focal length in millimetres by 14. A 1000mm telescope gives 71x, a 1400mm gives 100x.

How wide is the actual view?

The 18.9mm field stop divided by your focal length, times 57.3. In a 1200mm SCT that is 0.90 degrees, which is a little under two lunar diameters.

Why choose 82 degrees over a narrower field?

Two reasons: an object stays in view longer on an undriven mount, and there is enough surrounding sky that a cluster or a nebula sits in context rather than filling the frame edge to edge.

Does it need a 2-inch focuser?

No. The barrel is 1.25 inches, which is what makes this a wide-field eyepiece you can use in a small refractor or a travel setup.

Can I use it with glasses on?

15.6mm of eye relief is workable for many prescriptions and tight for some. Where taking glasses off is not an option, the long-eye-relief designs in the Explore Scientific range carry considerably more — tell us your situation and we will compare the figures for you.

Bottom Line

In short: a 14mm argon-purged waterproof eyepiece with an 82° apparent field, an 18.9mm field stop and 15.6mm of eye relief, all in a 256 g body on a 1.25-inch barrel — a wide field at medium power that any telescope with a standard focuser can take. If you would like help deciding how it fits alongside eyepieces you already own, send us the list and your telescope's focal length and we will work out the gaps.