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Explore Scientific 2" 100° Series Nitrogen-Purged Waterproof Eyepiece - 20mm

4.9 (12 Reviews) Read Reviews Write Review
Brand Explore Scientific
Part Number EPWP10020-00
Availability available

Product Info

Manufacturer Description

Using advanced computer design, combinations of low dispersion and high refractive index optical glasses, and durable multilayer deposition coatings, Explore Scientific 100° Series hyper-wide field eyepieces are optimized to produce high contrast, high resolution, and superior flat field characteristics. And yes, they are indeed ruggedized and waterproof to withstand the outdoor environment.

The visual effect of these eyepieces with their long eye-relief and their 100° apparent field is an extreme full-immersion experience. You have to try it understand the visual impact that these eyepieces produce.

Like all Explore Scientific eyepieces, the lens elements of the 100° eyepiece are meticulously cleaned and aligned before being installed in their precision machined lens barrels.

Each lens and lens grouping have EMD (Enhanced Multilayer Deposition) Coatings and are edge-blackened to eliminate light scatter and maintain image contrast. Contrast is further enhanced with baffles that mask and deflect unwanted stray light.

Each 100° Series Nitrogen-Purged Waterproof eyepiece is internally sealed and purged with inert, dry nitrogen gas to prevent internal fogging, to halt the intrusion of fine particulates and fungus, and to maximize the life of the internal coatings. To make sure, every 100° eyepiece is tested by submerging them down to 1 meter of water for 30 minutes.

Explore Scientific's eyepieces are backed with their exclusive Explore STAR Transferrable Extended Life of the Product Warranty. Limited Warranty is one year, which converts to the Explore STAR Transferrable Extended Life of the Product Warranty when product is registered within 60 days of purchase. We think that you will find Explore Scientific eyepieces rank among the finest obtainable and represent an outstanding value.

Reviews

4.9 (Based on 12 Reviews) 100% of reviewers recommended this product.
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    1. Guest

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      Review by Curron H.
      1526545877
      May 17, 2018

      4.0 Great views, couple of disappointments

      Pros:

      Cons:

      Comments:

      First eyepieces are all about the view you achieve from them. In that case this 20mm 100 degree gets a 5 star rating. Stars are sharp all the way to the edge, and the edge is way out there on this 100 degree view! So why 4 star rating then? Two reasons: 1, The black rubber grip around the eyepiece is frosting (turning white) due to uv exposure. This is problem with the formulation the rubber component was molded from. I expect in 10 years it will show signs of cracking and degrading. It's a cheap formulation, not well engineered. 2, The box the eyepiece came in was not the beautiful star map eyepiece box that Explore Scientific is famous for. This box is a plain cheap black box like you would expect from a cheap eyepiece, not a $400 eyepiece. I was really disappointed from that perspective. So hide the eyepiece during the daylight when the flawed frosted grip And ugly box can be seen, but bring it out when it is dark, the views through it are amazing!

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    2. Guest

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      Review by russ.will of Cambridge, UK.
      1427500800
      Mar 27, 2015

      5.0 What a beast!

      Pros:

      Strong Construction,Accurate,Quality Lenses

      Cons:

      Heavy

      Comments:

      I've had some meaty eyepieces (ES82 30mm, Meade 40mm SWA) in my time, but this thing still surprised me as I unboxed it. It's tall, very dense and is not going to be easy to switch back and forward between this and an Ortho unless you enjoy re-balancing your scope.

      When you put your eye to it, all of those concerns disappear as your entire view is filled with pin point stars that stay sharp until your into the last 5-10% of the field of view. To be fair, some of that field is out of sight unless you really jam your eyeball in there; you do have to go looking for the field stop and any concerns near it and it isn't comfortable on your eye's tendons to do so, so don't! Easier, is to get in close enough while remaining comfortable and reveling in the fact that there is no edge to what you're seeing.

      In my F10 LX200, where the ES100 20mm is ponying up 100x, the lack of internal reflections and on-axis flare makes this a very usuable and vertigo inducing lunar tool. Maybe not quite up there with a good Ortho, but then it has quantities that have a quality all of their own.

      For me this is one of the things that endear me most and that's image scale. The Moon (or Sun) are only filling halve of the AFOV, but that is a very large FOV and therefore the full disk is massive too. You can spend ages drinking in the whole spectacle AND focusing on details without chopping EPs back and forth. Lazy? Yes. Fun? Definitely!

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    3. Dick Gentry

      Dick Gentry New Member

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      Review by Dick of Dallas, Texas.
      1422662400
      Jan 30, 2015

      5.0 New favorite eyepiece

      Pros:

      Versatile,Accurate

      Cons:

      Comments:

      In the XT10i this eyepiece give excellent widefield views at relatively high magnifications and smaller exit pupils for darker background skies. The ES82 30mm sees much less time in the focuser since this ES100 20mm became part of the kit.
      In the LX200 16" the ES100 20mm eyepiece yields 203x, 30 arc' TFOV and a friendly 2.0mm exit pupil and is fantastic when used in the Leo and Virgo galaxy fields. It has enough magnification along with great clarity to give definition to PGC and IC galaxies in the Perseus I (Abell 426) cluster.
      This is certainly my new favorite eyepiece.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    4. Guest

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      Review by Navegante of Tenerife Canary Islands.
      1422662400
      Jan 30, 2015

      5.0 Best eyepiece of my collection

      Pros:

      Accurate,Strong Construction,Quality Lenses

      Cons:

      Heavy

      Comments:

      Best eyepiece I have used

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    5. Guest

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      Review by Bruno of Bratislava, Slovakia.
      1419897600
      Dec 29, 2014

      5.0 Best EP for my refractors

      Pros:

      Sharpnes,Quality Lenses,Afov,Strong Construction,Contrast

      Cons:

      Heavy

      Comments:

      Perfect eyepiece, tested on star clusters with my small telescope (SW 4" F5 achromat) the stars are pinpoint and very sharp and 4 deg FOV is great. With Big Brother (Meade AR152 F8) views are more than nice, in M42 I can see details and structures. With (3X Barlow) Jupiter has great contrast and I can see a lot of detail in atmosphere and Moon details and craters was really plastic. All I tried on suburban skys, I'm looking forward to test it in mountains.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    6. Guest

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      Review by John T of Sydney, Australia.
      1394928000
      Mar 15, 2014

      5.0 Brilliant in my 8SE SCT

      Pros:

      That Wide Wide Field,Quality Lenses,Easy to Use,Strong Construction,Sharp

      Cons:

      Heavy

      Comments:

      As I newbie I had read around various forums trying to gauge which wide-field EP would be a good complement to my 8-24mm zoom et al. I have a WO 2" diagonal and kept coming across the ES 100* 20mm as being especially sweet for an F10 SCT (102X mag).

      Usual excellent service from Agena - I have placed several orders with them, all 100% happy (no affiliation etc).

      This EP is just terrific in my 8SE:
      * all that 'spacewalk' talk went from hyperbole to reality in a flash!
      * very sharp image whether on constellations or clusters out to about 90-95% of the huge FOV, slight softening at the very perimeter
      * gives a good dark background in my medium-high LP area (Sydney)
      * beautiful build feel, darn solid yet it doesn't cause any balance issues for my 8SE (along with WO 2" diagonal, 9x50 RACI finder, Telrad)

      Couple of small things to note:
      * it does take a short while to get used to the eye positioning needed to get the most out of the FOV -- with the eye guard up, I find it restricts FOV by maybe 10% so I roll it down, which means getting used to your eyeball being so close to the lens...an art not a science
      * 2" nosepiece scrapes a little inside the WO 2" diagonal; not a big issue, it causes no marking on either the diagonal or EP (so far anyway) but just a little sticky.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    7. Guest

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      Review by Roger of Phoenix, Arizona.
      1386374400
      Dec 6, 2013

      5.0 Like walking among the Stars

      Pros:

      Sharp To The Edge,Water proof,Quality Lenses,Strong Construction

      Cons:

      Heavy

      Comments:

      The Explore Scientific 20mm 100 degree field of view gives sharp edge to edge pinpoint stars in my 16" DOB and in my William GTF 81mm finder scope. High Quality, priced right.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    8. Guest

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      Review by MrSmiley of Perth, Australia.
      1380758400
      Oct 2, 2013

      5.0 Superb Eyepiece, But Heavy!

      Pros:

      Dazzling Wide View,Strong Construction,Quality Lenses

      Cons:

      Heavy

      Comments:

      I almost have all the Explore Scientific 2" 100

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    9. Guest

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      Review by Mark of Kutztown, PA.
      1375833600
      Aug 6, 2013

      5.0 My most used EP

      Pros:

      Quality Lenses,Water proof,Strong Construction,High quality

      Cons:

      Heavy

      Comments:

      This is currently my favorite and most used EP. Either by itself or with my ES 2x focal extender. It is big and heavy so you will need to make sure to balance your scope. However, this is typical for 2" EP's with a large AFOV. Views are tack sharp all the way to the edge. I'm using in a F10 scope so it is a bit forgiving. This is one fantastic EP. ES continues to produce top notch optics at great price points!

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    10. Guest

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      Review by Marci1954 of Hercegszanto, Bacs-Kiskun,HUNGARY.
      1369958400
      May 30, 2013

      5.0 I would buy this product again and again

      Pros:

      Easy to Use,Accurate,Strong Construction,Quality Lenses

      Cons:

      Little heavy

      Comments:

      Extreme perfect design, beautiful "deep space" feeling. This is my favorite eyepiece.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    11. astroram

      astroram New Member

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      1359424740
      Jan 28, 2013

      5.0 Explore Scientific 20mm

      Pros:

      Comfortable, sharp, true spacewalk experience.

      Cons:

      Heavy, heavy, heavy in small scopes

      Comments:

      I have become quite addictive to widefield eyepieces. I own a few big telescopes including my C14 with 3950mm focal length!! The Explore Scientific line of eyepiece intrigue me with a lot of bang for your buck. After admiring ads for this new 20mm 100 degree FOV eyepiece I finally took the plunge. I choose Agena since I love their customer service and fast shipment. The eyepiece arrived with a bonus bolt case. This is one BEAUTIFUL looking eyepiece. It's about as heavy as the 14mm version. It is sleek in design. I tested it out in my C14, with almost 200 power and nearly a 0.5 degree TFOV and I was hooked. The image was tack sharp. I observed M42, M81 and M82 that first night out. Since then it's the first eyepiece I grab for in that Big Cat. Using digital setting circles, the generous FOV and high power make spotting small DSO's a cinch. I can't recommend this eyepiece enough. The only issue I might see is the weight in some smaller scopes, but in my larger scopes, that isn't an issue. When observing with my big CAT and 22 inch DOB, this eyepiece is used the majority of the time now. One look and you will be HOOKED.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No
    12. astroram

      astroram New Member

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      Review by astroramrx of SE PA.
      1358294400
      Jan 15, 2013

      5.0 ES 2" 100 degree 20mm eyepiece

      Pros:

      Quality Lenses,Strong Construction

      Cons:

      Heavy

      Comments:

      I have become quite addicted to widefield eyepieces. I own a few big telescopes including my C14 with 3950mm focal length!! The Explore Scientific line of eyepiece intrigue me lot of bang for your buck. After admiring ads for this new 20mm 100 degree FOV eyepiece I finally took the plunge. I choose Agena since I love their customer service and fast shipment. The eyepiece arrived with a bonus bolt case. This is one BEAUTIFUL looking eyepiece. Its about as heavy as the 14mm version. It is sleek in design. I tested it out in my C14, with almost 200 power and nearly a 0.5 degree TFOV I was hooked. The image was tack sharp. I observed M42, M81 and M82 that first night out. Since then its the first eyepiece I grab for in that Big Cat. Using digital setting circles the generous FOV and high power make spotting small DSO's a cinch. I can't recommend this eyepiece enough. The only issue I might see is the weight in some smaller scopes, but in my larger scopes, that isn't an issue.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

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      Specifications

      Apparent Field of View 100°
      Barrel Size 2" (50.8mm)
      Bolt Case Included Yes - Free Agena Eyepiece Container
      Bolt Case Size Agena 85x120mm
      Coatings EMD (Enhanced Multilayer Deposition) Coatings
      Design Combination of: Dense Crown, Light Crown, Dense Flint, and Lanthanum Optical Glasses
      End Caps 2
      Eye Relief by Design 14.5mm
      Filter Threads Standard 2" Filter Thread (M48 x 0.75)
      Focal Length 20mm
      Lens Elements 9
      Rubber Eye Guard Rubber Folding Type
      Blackened Lens Edges Yes
      Additional Information Body: Anodized Black Aluminum; Laser-Etched Description and Serial Number; Rubber Grip: Internally O-Ring Sealed and Nitrogen Purged

      Barrel: Stainless-Steel, Double Taper, Accepts Standard Filters
      Manufacturer Explore Scientific
      Eyepiece Focal Length 15.1mm - 20mm
      Eyepiece Field of View Over 80 degrees
      Eyepiece Series Explore Scientific 100°
      Barrel Type Tapered barrel
      Eyepiece Weight 34oz (963.88g)