Explore Scientific 11mm 82° field argon-purged waterproof 1.25" eyepiece


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The "picture window on space" viewing experience of this 82° field Explore Scientific 11mm 1.25" argon-purged eyepiece gives you the magnification you want, without cramping your field of view like an ordinary high power eyepiece.
Our Product #: ES8211A
Explore Scientific Product #: EPWP8211-01

Product Description

This 11mm Explore Scientific is an exceptional medium high power/ultra wide field eyepiece that's great for resolving globular clusters, picking up detail in smaller galaxies, investigating the Moon and planets in depth, and more. It works with any type of telescope, from a fast focal ratio Dobsonian reflector to a long focal ratio achromatic refractor or Maksutov. The wide field of the 11mm Explore Scientific makes observing through it feel like you're gazing serenely through a "picture window on space" rather than squinting through an eyepiece. It provides an almost ideal match of an 8" f/10 Schmidt-Cassegrain's resolving power to the resolving power of your eye, for maximum lunar and planetary detail.

In addition to its wide, wide field the 11mm 82° Explore Scientific comes with another very useful benefit. 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 seven 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 10" f/4.5 Dobsonian reflector gives you a full 0.79° field at 103x with this eyepiece, half again as wide as the full Moon, for eyepiece filling views of showpiece nebulas like Orion. Even an 8" f/10 catadioptric has a 0.45° field at 182x that's almost as wide as the full Moon itself, for thrilling close-up views of our nearest celestial neighbor. Use the calculator in the "formula" tab above to see just how wide a field you'll get with your particular telescope.

At 15mm, the eye relief is surprisingly good, although eyeglass wearers will still see a somewhat vignetted image. This isn't as much a problem as you might think, as the 82° field of view is so wide that even non-eyeglass wearers have trouble seeing the whole field at once. This is an eyepiece that shows you a "picture window view" of space for a true full-immersion observing experience. With its unconstricted view, your eye relaxes, allowing you to easily use the "averted vision" technique to study faint details across a huge field of view.

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. Here's a link to the full details on this unique transferable lifetime warranty.

Tech Details

Barrel Size 1.25"
Eye Relief 15mm
Field of view 82
Focal Length 11mm
Number of optical elements 7
Weight 10 oz.
Warranty 1 year, extendable to lifetime


Review by:
This EP is really nice for it's affordability, and is one of 3 that is always with me when I am observing. It's affordable enough that I don't worry when taking it to outreach, but it's good enough that if I am travelling light it can be one of only 2 EPs on some trips. I've used it across the board from my 80mm ST all the way through to my 12" dob, and been very happy with it. (Posted on 10/31/2019)
Review by:
I've used this in my 8" dob, SW 130PDS, and 90mm Mak-Cass. Great image correction out to the last 10%. Eye relief feels a tad tight, especially if the eye cup isn't rolled down. Great solid construction. (Posted on 10/19/2019)
Review by:
The ES 82 11mm is a really well made and executed wide field eyepiece. It's one of my most used as it just puts up a pleasing view regardless of what scope I use. Mine arrived with a fleck of something between two elements. I didn't notice it initially and it doesn't hurt anything but it's there. (Posted on 9/26/2019)
Review by:
I own three 82 deg eyepieces. Definitely a step up from most eyepieces you find in telescope bundles. They are substantial, well constructed, and a pleasure to use. They go on sale from time to time which makes them an even better value. Excellent optically when used with my Esprit 120 or my other smaller AT refractors. (Posted on 9/3/2019)
Review by:
Pleased with the FOV and overall performance of this eyepiece. An excellent addition for general viewing. (Posted on 7/30/2019)
Review by:
I love this eyepiece. It's my go to EP for my small refractor. It's a clear, widefield instrument that presents a good view of the planets and the moon. I use it quite a bit at star parties, where it's easier for those who may have never looked through a scope to find the image for the first time. I have other ES eyepieces, and I enjoy them all. I'll be buying more! (Posted on 7/24/2019)
Review by:
I just keep reaching for this one. I love the views through it with my telescope (100mm F/9 ED refractor). The eye relief is good, and the 82 AFOV gives an immersive viewing experience. Bright and sharp images. And it costs a fraction of what certain other EPs with similar specs cost ; ) (Posted on 1/14/2019)
Review by:
I use this with both a 12.5 f4.8 Dob (109x/0.75deg FOV) and an 11" SCT (271x) - Fantastic! Good medium power eyepiece. (Posted on 1/4/2019)
Review by:
I've owned all the ES82s over the years. The 11mm is one of my favorites. Eyepiece is sharp out to about 90% of the FOV in my F/5 and F/6 scopes. There is a bit of lateral color at the extreme edge of the FOV which is hard to notice due to the 82 degree FOV. For the money these are hard to beat. I have owned 2 of these over the years and sold them for 100 degree eyepieces but I am going to get a 3rd one for the ergonomics. My favorites are the 11mm and 6.7. When these are on sale it is a 5 star review instead of a 4. (Posted on 12/30/2018)
Review by:
purchased this originally to use with a 90 mm Mak on a manual mount. It gave great high power wide views. pretty comfortable without glasses with the eye cup up, but not enough eye relieve to use with glasses and see the whole field.

fit and finish were also very nice. (Posted on 12/10/2018)
Review by:
This is a great all around eyepiece. I started off with an inexpensive 8" f5.9 dob and it was a wonderful experience to go from the included eyepieces to the wider field of view of this eyepiece. I did a lot of research and decided to start with this company and this eyepiece. I now have the 4.7mm 82 degree and the 24mm 68 degree eyepieces from ES. They are all great and a total bargain. (Posted on 12/9/2018)
Review by:
I use this on most every object I observe. Through 14 inch dob views are wonderful. pinpoint stars to the edges no defects at all, no astigmatism. Every ES eyepiece I have observed with has been the same quality. (Posted on 11/18/2018)
Review by:
I have owned this eyepiece for approximately two years and it has been one of my go to eyepieces. I typically use this eyepiece to view every object I go to weather it is a planet or globular cluster. The stars appear very sharp even at the edges and it never seems to for over. (Posted on 10/23/2018)
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