Dismiss Notice
New Cookie Policy
On May 24, 2018, we published revised versions of our Terms and Rules and Cookie Policy. Your use of AstronomyConnect.com’s services is subject to these revised terms.

More Views

Agena 1.25" ED Eyepiece - 3.8mm

4.5 (4 Reviews) Read Reviews Write Review
Brand Agena AstroProducts
Part Number -
Availability

Product Info

Manufacturer Description

ED stands for "Extra-Low Dispersion". These eyepieces use optical glass in which two of the lens elements are crafted from ED glass which is a special grade of glass that provides much superior refractive properties as compared to standard optical glass. This results in much better color correction. ED glass is often the type used in many expensive camera lenses and high-end refractor telescopes costing thousands of dollars.

Our ED-series eyepieces are available in a 1.25" barrel in 10 focal lengths (2.3, 3.8, 5.2, 7.5, 9.5, 12.5, 14, 18, 21 and 25mm). They feature a six-element lens design that provides significantly reduced chromatic aberration, high resolution and excellent sharpness without compromising image brightness. Their long 20mm eye relief means that even eyeglass wearers can take in the full 55-degree apparent wide field of view (AFOV).

All ED-series eyepieces are fully broadband multi-coated for maximum image brightness. Lens edges are blackened throughout for improved contrast. The eyepiece housing is precision machined from aluminum and clear-anodized to a lustrous finish. A rubber traction ring ensures a secure grip and a rubber eyeguard helps position your eye to block out stray light. The chrome barrel features a setscrew recess for added security. All eyepieces are parfocal and are threaded to accept standard 1.25" filters. Each eyepiece comes in a bolt case with two plastic end caps. Compare these with the ED eyepieces sold in very similar focal lengths by two of the "Big-3" telescope companies and you'll realize the savings we offer.

Important note: Depending on your telescope, this eyepiece may provide magnifications that are too high! While it can be very useful for viewing the Sun, Moon, brighter planets and terrestrial objects, it is not for everyone or for common viewing conditions.

Before buying, please make sure that you are using realistic magnifications with your telescope. A good rule of thumb is that under very good conditions and with a very good telescope, the maximum power you will be able to use is about 50x of magnification per inch of telescope aperture. With average telescopes and/or average conditions, you might be limited to 30x of magnification per inch of telescope aperture. So for example, if you have a 5" telescope, under typical conditions you might typically use 5x30 = 150x of magnification, and 5x50 = 250x of magnification at best. If your telescope has a focal length of, say, 1000mm, then this eyepiece will result in a magnification of 1000 / 3.8 = 263x which is probably too much for this telescope.

Also, when you magnify an object, its light is spread over a larger area. Since the brightness of the object being viewed hasn't changed, this means that the image you see will be fainter. Double the magnification and the image will get 4 times fainter. This is a basic law of physics, but people often forget this and complain that the "image is not bright enough" when they increase the magnification to very high powers.

Boosting the magnification beyond the recommended maximum for your telescope aperture is not realistic. This is bound to result in image break-down, causing faint, fuzzy images, focusing difficulties, increased color around objects and general disappointment. Use the eyepiece in the right settings and with the correct expectations, and you will enjoy it.

Reviews

4.5 (Based on 4 Reviews) 100% of reviewers recommended this product.
Rating Distribution
Sort by
  • Date
  • Rating
  • Useful
    1. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Alex of Mexico.
      1319846400
      Oct 28, 2011

      4.0 Great EP for the price

      Pros:

      Quality Lenses,Easy to Use,Strong Construction,Lightweight

      Cons:

      Comments:

      This eyepiece is great, I use it exclusively for planetary viewing with my 8" F/6 reflector, getting 315x which is just the right amount of power to see planets in nice seeing conditions. Construction seems pretty good, and to me, is very light considering its quite big size. Image is sharp and clear in most of the field of view, edges become distorted but c'mon this is not a $250 eyepiece, hence, this is a perfect budget planetary eyepiece.

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

      This review was provided courtesy of AgenaAstro.com

    2. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Craig of Portland, OR.
      1307318400
      Jun 5, 2011

      5.0 HD eyepiece 3.8mm

      Pros:

      Very sharp planet view

      Cons:

      Comments:

      I took this out the other night when the visibility was good here in Portland. I got clear views of the ring bands and cloud bands on Saturn. This ones good for planet observation. AgenaCraig

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

      This review was provided courtesy of AgenaAstro.com

    3. ApexMI_bob

      ApexMI_bob New Member

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by ApexMI_bob of Algonac, MI.
      1255651200
      Oct 15, 2009

      4.0 Very happy with my first results

      Pros:

      Quality Lenses,Strong Construction

      Cons:

      Comments:

      Very sharp eyepiece with excellent contrast. I've only had a couple nights out with it and am still getting used to the long 20mm eye relief. But I am very happy with this purchase and will be adding more Agena eyepieces to my collection.

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

      This review was provided courtesy of AgenaAstro.com

    4. skooter60

      skooter60 New Member

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Skooter60 of Hatfield PA.
      1238457600
      Mar 30, 2009

      5.0 Great Planetary EP

      Pros:

      Quality Lenses,Strong Construction

      Cons:

      Heavy

      Comments:

      This was used in a F/5 reflector and F/5 refractor, the views are crisp and sharp. It also cut down on the CA I normally get when looking at bright objects. The eye releif is great and it just looks and feels like a quality EP.

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

      This review was provided courtesy of AgenaAstro.com

    Sort by
    • Date
    • Rating
    • Useful

      Specifications

      Apparent Field of View 55°
      Barrel Size 1.25" (31.7mm)
      Bolt Case Included Yes - Manufacturer Supplied
      Bolt Case Size -
      Coatings Fully Broadband Multi-Coated
      Height (with Eye Guard) 5.0" (126mm)
      End Caps 2
      Eye Relief by Design 20mm
      Filter Threads Standard 1.25" Filter Thread (M28.5 x 0.6)
      Focal Length 3.80mm
      Lens Elements 6
      Rubber Eye Guard Yes
      Blackened Lens Edges Yes
      Manufacturer Agena AstroProducts
      Eyepiece Focal Length 5mm and Under
      Eyepiece Field of View 51 - 60 degrees
      Eyepiece Series Agena ED
      Barrel Type With safety undercut
      Eyepiece Weight 7.50oz (212.62g)