Explore Scientific 30mm 82° field argon-purged waterproof 2" eyepiece


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This 82° field Explore Scientific 30mm 2" argon-purged waterproof eyepiece gives you the big picture, making you feel like you're relaxing in front of an expansive picture window on the Universe, rather than squinting through an eyepiece.
Our Product #: ES8230A
Explore Scientific Product #: EPWP8230-01

Product Description

This 2" 30mm Explore Scientific is an excellent low power eyepiece with an ultra-wide 82° field of view, one so wide you have to move your head from side to side to see it all. It is particularly suited to get the maximum image brightness and field of view out of big Dobsonian scopes, but will work well with any scope that can use 2" eyepieces, even an f/15 Maksutov. Viewing through this 30mm Explore Scientific makes you feel like you're floating above the Earth, taking a space walk, rather than looking through a telescope eyepiece. If you want a truly relaxed and unconfined "picture window" view of the Universe, this is the eyepiece for you.

With an f/4.5 Dobsonian reflector, this 30mm eyepiece has a very large 6.7mm exit pupil larger than some observers' eyes can dilate. That can effectively waste some of the Dob's light gathering capacity for those observers, as some of the full light cone will fall on their iris, rather than entering his or her eye. Even so, many observers are willing to trade a little light gathering for the jaw-dropping fully-immersive view through this 82° apparent field eyepiece. If you want to see the big picture, this is an eyepiece you will treasure for years to come.

In addition to its wide field, the 30mm Explore Scientific has an extra benefit for you. It is O-ring sealed and argon-purged to be 100% waterproof. This prevents internal fogging in the eyepiece; keeps the interior dust-and fungus-free; and makes it easier to clean, as there is no risk of excess cleaning solution getting trapped between the lenses.

The latest computer design programs have been used to optimize its performance. Its six element/four group design uses low dispersion and high refractive index lenses and full multicoatings for high contrast, high resolution, and flat field images across its very wide 82° field of view. The lens edges have been blackened to improve contrast.

A 12" f/4.5 Dobsonian reflector gives you a full 1.79° field at 45.7x with this eyepiece, well over three lunar diameters, and easily able to encompass all of the Pleiades or Orion in one field. You get over seven minutes of uninterrupted observing with such a scope while an object drifts from one side of the sharp and flat eyepiece field to the other. That's plenty of time for multiple observers to look at the same object, or for you to absorb as much detail as possible, before having to reposition the scope. Even an 8" f/10 catadioptric has a 1.23° field that's almost two and a half lunar diameters across, for thrilling views of the larger nebulas, like the Omega and Orion. Use the calculator in the "formula" tab above to see just how wide a field you'll get with your particular telescope.

With 21mm of eye relief, this 30mm Explore Scientific eyepiece provides unvignetted views for eyeglass wearers, although the 82° field of view is so wide that even non-eyeglass wearers can't see the whole field at once. All observers have to move their eye from side to side to see out to the field stop.

The eyepiece has a soft fold-down rubber eyecup and comes with dust covers for both ends of the eyepiece.

This individually serial numbered Explore Scientific eyepiece is backed by a limited one year warranty, which will be extended to an Explore Scientific transferable lifetime limited warranty when its warranty card is registered with Explore Scientific within 60 days of purchase. This link will give you full details on this unique transferable lifetime warranty.

Tech Details

Barrel Size 2"
Eye Relief 21mm
Field of view 82
Focal Length 30mm
Number of optical elements 6
Weight 2.2 lbs.
Warranty 1 year, extendable to lifetime


Review by:
Like the others in its line, ES 30mm 82 is an excellent eyepiece which gave superb, contrasty, sharp to the edge views in my AT102ED. The largest and heaviest of the bunch, this eyepiece weighs well over 2 pounds, so keep that in mind. For the price, it is an excellent value compared to a couple of "more expensive options." It has a massive 82-degree AFOV and a nice rubber eye guard that you can rest your eye into pretty comfortably. This eyepiece exudes quality; it is very well made.

There is one caveat, however. The eye lens is recessed so deeply into the body that I had to push my eye all the way in to be able to see the entire field of view. With glasses, I was unable to see the entire field, only about 75% or so. In terms of comfort, it felt similar to looking through a 100-degree AFOV eyepiece with 13mm of eye relief. I would say the usable eye relief on the 30mm 82 is about the same.

If you have to wear glasses at the eyepiece or otherwise need long eye relief, there are better options. Otherwise, you'd be hard-pressed to find a better value than the ES 82 line. (Posted on 11/5/2019)
Review by:
The ES82 30mm is a joy to use when the situation calls for a low power wide field eyepiece. The views are very good and the 82 degree field is perfect with decent eye relief and large eye lens. It’s worthy of a 5 star rating despite some minor flaws. The thing is so darn heavy, perhaps if I had a fancier scope that wouldn’t be a problem. The eye lens is excessively recessed which effectively reduces the eye relief, a shame. I don’t care for the ES tapered barrel design. I’ve never felt like the field is 100% corrected but it’s very good. (Posted on 10/24/2019)
Review by:
The ES82 30mm is a fantastic high performance wide field eyepiece that provides the user with a similar performance to the more expensive brands of EP's. I use this with my F10 8" and 11" Celestron CPC's and it works wonderfully. Very pleased with the performance and the price. (Posted on 9/10/2019)
Review by:
Good eye relief, 0.88 degree field of view, 93x, in C11", 2800mm focal length. Wish it was lighter as this C11 is maxing out the Celestron Advanced VX mount. The 100 degree 30mm would give 1.1 degree field of view (Posted on 7/23/2019)
Review by:
The ES 82 degree, 30 mm eyepiece gives a balanced performance in a C8 with a good actual field of view (~ 1.2 degrees), useful magnification (~ 70x) and exit pupil of 3 mm (in the eyes region of good visual sharpness). For what its worth Sky Tools 3 recommended it from my stable for my mid July urban observing targets and I enjoyed the views it gave of M 10, IC 4665 and IC 4756 before the moon further washed out my mid-city skies. (Posted on 7/22/2019)
Review by:
This is a fantastic entrance to the premium eyepiece market. The 82 degree field of view really makes a difference- as an eyeglass wearer I have to get pretty close to even see the whole field. In my 6" f/5 newt I get a 3.3 degree true field of view; it's amazing for really big nebulae like NGC 7000 or the Veil. There's basically no false color and the field is very flat. The only possible downside is that this eyepiece is pretty heavy- it can definitely unbalance your scope, and I have to pull it out of the focuser about three quarters of an inch to get it to focus properly. Neither of these are dealbreakers, and I really recommend this eyepiece to anybody. (Posted on 7/22/2019)
Review by:
This is a amazing eye piece with amazing views, I don't know why some one would want more than 82 degrees. Some one described it as looking out a bubble window from the ISS. There's so much to see that you literally have to look around in the eye piece. It's a big and heavy eye piece as well so you don't want slippery hands when changing it out.. (Posted on 12/11/2018)
Review by:
The ES82 30mm is a great high performance widefield eyepiece that happens to come at a lower price than its capability might lead you to expect. I think there are reasons to PREFER it over some others, the Terminagler for instance. Its flatter field is easy to see. I have long said they should just package these with 10 and 12" mass market Dobs as it is a perfect match. (The bargain Astro-Tech coma corrector works very well with the ES82 30mm.) (Posted on 10/30/2018)
Review by:
Gives amazing views in a 12" Dobsonian; wide enough to cover 90% of M31 and include M110. There are other eyepieces that cost less and offer an even wider field but they either distort the field so you must pick which portion of the view you want in focus or they magnify so little that the sky isn't as dark. (Posted on 10/24/2018)
Review by:
Amazing wide view with great flat useable field, even in my 12" f/5 dob. Also excellent in my refractors as well. pin point stars in glob and open clusters. A deepsky observer's tool of choice for large objects, finding targets, and getting those awesome context views. (Posted on 10/6/2018)
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