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Agena 1.25" Wide Angle High Definition Eyepiece - 20mm

3.8 (4 Reviews) Read Reviews Write Review
Brand Agena AstroProducts
Part Number -
Availability available

Product Info

Manufacturer Description

Outstanding Planetary and Lunar Eyepieces

Primarily made for planetary observation, these 1.25" fully multicoated (FMC) eyepieces give maximum detail and definition across the entire 58 degree field of view (FOV). A great value, these eyepieces are exceptional at nearly eliminating lateral color aberration and light scatter often associated with more expensive eyepieces that are better suited for deep space objects.

Each eyepiece has 5 lens elements in 3 groups - with the exception of the 20mm eyepiece which has 4 groups.

Agena WA HD Planetary Eyepieces vs. More Expensive UWA Eyepieces:

Premium (and costly!) eyepieces that have similar wide fields of view need many exotic glass elements to achieve that wide field of view - as many as 9 lenses or more. More lenses mean more cost and more glass, which attenuates the amount of light you see. That also means there are more air-to-glass surfaces that can scatter light - reducing contrast and sometimes causing multiple reflections (ghosting) when viewing very bright objects such as the Moon and planets. Extra lenses can also mean compromises in the overall design that can often lead to other issues.

One such issue of all that glass is lateral color aberration that appears as a cloud of false color around bright objects. Another issue is light scatter seen as a distracting halo or glow around bright objects. This can also reduce contrast. Our 58 degree eyepieces provide high contrast, no scattered light, and the highest possible definition.

Long Eye Relief - Up To 20mm!

Our eyepiece eye relief averages around 15mm and is as much as 20mm in the 25mm focal length model. Even the 2.5mm eyepiece has almost 17mm of eye relief! Experienced observers will truly appreciate such generous eye relief at significant magnifications.

Excellent Fit and Finish:

These eyepieces are fully internally baffled and all internal spacers have antireflection microbaffles on their edges with flat black anodizing to reduce reflections. Every air to glass surface is broadband multicoated for peak light transmission and outstanding contrast on subtle lunar and planetary detail. The lens edges are blackened to eliminate internal reflections.

Each eyepiece has a flexible rubber fold-down eyeguard. Dust covers are provided for both ends of each eyepiece. A groove is machined into the nose piece barrel to ensure the eyepiece is less likely to fall out of the diagonal or focuser.

Real World Results:

In an independent test the 4mm Agena WA HD planetary eyepiece, for example, performed visibly better than a 2x Barlowed 8mm top-tier Plossl costing about $100 - with an additional 6 degrees FOV. Another field test showed that our planetary eyepieces kept a better, more natural coloring of Jupiter across the entire field of view than a much more expensive brand at the same focal length. And the longer focal length eyepieces still provided excellent edge performance and true flat field even when used in a fast (f/5) scope. Such results are truly amazing, considering the low price of the Agena WA HD Planetary eyepieces.

Reviews

3.8 (Based on 4 Reviews) 75% of reviewers recommended this product.
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    1. Guest

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      User Notes:
      Review by Dean G. of PA.
      1443225600
      Sep 25, 2015

      4.0 Nice eyepiece

      Pros:

      Lightweight

      Cons:

      Comments:

      A very nice eyepiece for low to medium magnification. I use it primarily for deep space observing. The generous eye relief is great for eyeglass wearers. The views are very good and so is the contrast. The eyepiece is lightweight and I do not have to rebalance my telescope. I do recommend it.

      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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      User Notes:
      Review by Dude of Holland.
      1435536000
      Jun 28, 2015

      3.0 It's ok, but not great for fast scopes

      Pros:

      Lightweight,Strong Construction,Easy to Use

      Cons:

      Not for fast scopes,Not The Best At F4,Not Great In Fast Scopes

      Comments:

      This eyepiece is lightweight and fairly well made. The twist eyecup works well. Eye relief is very good. I didn't have any problems with blackouts or kidney beaning, like I did with a 25mm Celestron X-Cel LX. It has 5 lens elements in 4 groups. The center of the view is sharp, but the outer 1/3 of the edge is a bit fuzzy in a fast f/4 reflector scope. Maybe works better in slower scopes? I got it on sale to use as a wide angle 'finder' eyepiece. It works ok for that purpose.

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

      This review was provided courtesy of AgenaAstro.com

    3. Guest

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      Review by Penguinx64 of Holland.
      1424995200
      Feb 26, 2015

      4.0 Works great in my Starblast 4.5

      Pros:

      Accurate,Easy to Use,Strong Construction,Quality Lenses

      Cons:

      Weighs Almost 6 Oz,Bigger Than I Expected

      Comments:

      Seems as good as most Plossls, but with a wider 58 degree field of view and 20mm eye relief. It has a twist eyecup with a rubber eyecup too. I got this eyepiece on sale for 1/3 the price of a 20mm Tele Vue Plossl.

      Great low magnification view of the Moon in my Starblast 4.5 f/4 reflector at 22.5x magnification. I could see lots of details in the craters with good contrast. Nice views of the Moon with a 2x barlow at 45x and a 3x barlow at 67x. Jupiter looked good with this eyepiece barlowed too. The 2 major cloud bands were visible and 3 moons were sharp. The 4th moon must have been hiding.

      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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      User Notes:
      Review by Nate of New Orleans, LA.
      1422662400
      Jan 30, 2015

      4.0 Quality budget eyepiece

      Pros:

      Quality Lenses,Easy to Use,Compact,Strong Construction,Accurate

      Cons:

      Comments:

      I use this lens with an 8" reflector and get great results, eye relief is much better than what came with my scope. Good budget EP. Great step up from stock that won't break the bank.

      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 58°
      Barrel Size 1.25" (31.7mm)
      Bolt Case Included Discontinued Item
      Bolt Case Size Agena 52x80mm
      Coatings Fully Multi-Coated
      End Caps 2
      Eye Relief by Design 18mm
      Filter Threads Standard 1.25" Filter Thread (M28.5 x 0.6)
      Focal Length 20mm
      Lens Elements 5
      Lens Groups 4
      Rubber Eye Guard Yes
      Blackened Lens Edges Yes
      Manufacturer Agena AstroProducts
      Eyepiece Focal Length 15.1mm - 20mm
      Eyepiece Field of View 51 - 60 degrees
      Eyepiece Series Agena WA HD
      Barrel Type Tapered barrel
      Eyepiece Weight 5.90oz (167.26g)