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Agena 1.25" Starguider Dual ED Eyepiece - 25mm
| Brand | Agena AstroProducts |
| Part Number | E-AG-SGED25 |
| Availability | available |
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Product Info
Manufacturer Description
With a true flat field and two high quality ED glass elements of different glass types, the new Agena StarGuider Dual ED eyepieces are characterized by a significantly high contrast image. These 1.25" fully multicoated (FMC) eyepieces give maximum detail and definition across the entire 60 degree field of view (FOV). This feature is especially useful for telescopes without tracking capability where the object drifts across the field of view during observation. 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.
The eyepieces are parfocal, minimizing the amount of refocusing needed when switching from eyepiece to eyepiece within the series.
Agena Dual ED Eyepieces vs. More Expensive 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. This results when different wavelengths (colors) of light pass through the eyepieces focal plane at different points and appear 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. Light scatter and lateral color are rarely seen in very wide field eyepieces when observing faint deep sky objects, but they become very apparent when viewing lunar, planetary, and double star objects. These objects don't need an extra-wide field of view to see small details and subtle contrast differences. Our 60 degree eyepieces provide high contrast, no scattered light, and the highest possible definition.
Agena Eyepieces - Rooted in Solid Design:
Orthoscopic and Plossl eyepieces have traditionally been the designs of choice for lunar, planetary, and binary star/star cluster observations. Their low number of lenses (typically four) and air-to-glass surfaces give better contrast and definition than the more exotic extra wide field eyepieces. A high quality orthoscopic or Plossl eyepiece on a good telescope gives views of Mars, Jupiter, and Saturn that can be breathtaking. But even these designs can be improved upon for lunar and planetary use.
Long Eye Relief - Up To 20mm!
Agena's StarGuider Dual ED eyepieces are the first long eye relief eyepieces with a comfortably wide field for planetary observing that also give the sharpness, contrast, and lack of lateral color and light scatter of the best orthoscopic and Plossl designs. What they don't have is the limited eye relief and restricted fields. Our eyepiece eye relief averages around 18mm and is as much as 20mm in the 25mm focal length model. Even the 5mm eyepiece has almost 16mm of eye relief! Experienced observers will truly appreciate such generous eye relief at significant magnifications.
The nicely machined body is rubberized and scalloped grooves around the circumference at the top provide a secure grip in all conditions.
Sharpness, Great Contrast and Flat Field of View:
With up to six lens elements in this unique design, these eyepieces are fully internally baffled and all internal spacers have antireflection microbaffles on their edges with flat black anodizing to reduce reflections. The field stop also has microbaffles in its edge to reduce off-axis flaring and produce a sharply delineated field edge. 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.
The eyepieces have a twist-up eyecup that can be raised or lowered as much as 11mm to provide the eye relief you find most comfortable. Spherical aberration of the exit pupil is well controlled, so there are no serious blackouts or kidney-bean effects if you move your eye slightly off the axis. 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 if the capture screw becomes accidentally loose.
Technical data:
- Focal length: Available in focal lengths of 5mm, 8mm, 12mm, 15mm, 18mm and 25mm
- 1.25" with filter thread
- Field of view: 60°
- Fully multi-coated on each glass/air surface
Reviews
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Dec 5, 2018
Excellent in a slow scope
Pros: Cons: Comments:My four-star rating for the 25mm Agena Starguider Dual ED eyepiece is a compromise due to very different performance in fast and slow telescopes.
Bottom Line: Would you recommend this item? Yes
The eyepiece shows a clear and sharp image in my 114mm f/7.9 newtonian reflector. The 60° field of view is pleasing and the eye relief is comfortable. It's a five-star eyepiece in a slow scope.
Unfortunately, I found the eyepiece unsuitable for my 130mm f/5 newtonian. Curvature of field causes stars near the edge to be badly out of focus. I'd rate it only a two-to-three-star eyepiece in a fast scope.This review was provided courtesy of AgenaAstro.com
Nov 21, 2018Excellent in a fast scope
Pros: Cons: Comments:My four-star rating for the 25mm Agena Starguider Dual ED eyepiece is a compromise due to very different performance in fast and slow telescopes.
Bottom Line: Would you recommend this item? Yes
The eyepiece shows a clear and sharp image in my 144mm f/7.9 newtonian reflector. The 60° field of view is pleasing and the eye relief is comfortable. It's a five-star eyepiece in a fast scope.
Unfortunately, I found the eyepiece unsuitable for my 130mm f/5 newtonian. Curvature of field causes stars near the edge to be badly out of focus. I'd rate it only a two-to-three-star eyepiece in a fast scope.This review was provided courtesy of AgenaAstro.com
Jul 8, 2018great value and quality
Pros: Cons: Comments:I purchased this and the 15mm version after reading in a couple of places that they were a great value. They seem to be just that. I coupled them with a 2x Televue barlow. I currently have an inexpensive 5" Dobson telescope. I would not say they are overkill. In fact, they add a lot of quality to the viewing experience. They should continue to serve me well as I move to a larger and more expensive scope in the future.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 20, 201825mm Agena Starguider Dual Ed
Pros: Cons: Comments:I have a Nexstar 102 SLT with a 6.47 focal ratio and this series of eyepieces are much better than the ones that came with the scope. I use the 25mm for finding objects or sometimes just for scanning different areas of the sky. Clear views and decent field of view.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jan 5, 2018Sharps and confortables views
Pros: Cons: Comments:I did not like using my 25mm Sirius Plossl eyepiece because of its small perfect focus point. With this eyepiece I do not have that problem and it is very comfortable to see through it, besides that it looks better.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Ronald Zincone New Member
- Skill Level
- Unknown
- Time with Product
- Unknown
- User Notes:
- Review by Ronnie Z.
May 28, 2017Nice heft. Great grip. No gripes.
Pros: Cons: Comments:The Agena 25mm ED is a keeper for me. Everything about it from the fit and finish to the FOV are perfect. The free bolt bottle is just the icing on this tasty bit of cake with its clean, crisp images across the entire field. Would i recommend the eyepiece to a friend? Without hesitation.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Nov 19, 2016Best in my PST
Pros:Quality Lenses,Compact,Easy to Use
Cons: Comments:I have the whole set of Dual ED eyepieces and find them more comfortable and easier to use than any other I've tried. Those others include ES 82 degree and Celestron Luminos eyepieces, glass costing 2-3x more than these. Dual EDs do have a narrower AFOV than the ES and Celestron, but what you get is a whole lot more accessible. The whole field of view is visible without having to move your head around or adjusting the height of the eyecup. I have used them in slow and fast telescopes. In the fast ones edge of field distortions are significant, but not much more than any other eyepiece. On the slow scopes distortions are not an issue. What compelled me to write his review is how well it works in my Coronado PST. The PST is a difficult telescope to use because of its narrow field stop. All eyepiece require precise eye positioning to get a good view. When you get the position correct, the view is worth every penny. The 25mm Dual ED's twist-up eyecup puts your eye in exactly the right position every time. It gives the most wiggle room of any eyepiece I've tried. The sun is the right size to keep it the field long enough for your eye to adjust the the H-alpha. It is the go-to eyepiece for this scope. It's the only eyepiece we ever use for public outreach with the PST.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
eyedoc1984 New Member
- Skill Level
- Unknown
- Time with Product
- Unknown
- User Notes:
- Review by Eyedoc of Rust belt state.
Sep 29, 2016Great value for longer focal length scopes
Pros:Quality Lenses,Easy to Use,Accurate,Strong Construction
Cons: Comments:These are fine eyepieces, particularly when used with long focal length telescopes. Some have complained about the 25mm Starguider's peripheral astigmatism when used with fast, short focal length ED refractors, but I haven't used it in that application. That said, this is not a Televue Nagler or Ethos, but it doesn't cost like either of those EPs either. For the SCT or MCT user, the Starguiders are a great value. Solid, good eye relief, well constructed.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Feb 4, 2016Most Used Eye Piece In My Collection
Pros:Accurate,Quality Lenses,Strong Construction,Easy to Use
Cons: Comments:This eye piece is my go-to. Every chance I get to take my scope out this is the eye piece I always start with. Awesome field of view and crystal clear optics. I think I have gotten muscle memory because I can set my focus and set this eye piece in and I am within .5 MM of true focus. It has been cold some nights and the Agena Starguider eye piece is by far the easiest to grab. You don't think about these things in the summer but wow does it come into play on cold nights.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jan 31, 2016Great EP but Poor Filter Threads
Pros:Quality Lenses
Cons:Loose Filter
Comments:I truly loved this eyepiece. I thought it was definitely a step up from the Zhumell EP that came with my 8" f/5.9 DOB. I think it produced a very bright image with very good contrast. I think at least 70 or maybe 80% of the field produced pinpoint stars and then one could notice some small amount of flaring. They were very lightweight and easy to turn up the cup.
Bottom Line: Would you recommend this item? Yes
The only issue that caused me to return it was the fact that a DGM filter would not screw it. The threads on my 25 mm were cut too wide such that I could slip the filter into the bottom without a single turn. I understand that every manufacturer has tolerances and obviously I got a EP and filter from opposite sides of the spectrum. Not wishing to have to find a solution, I opted to return it and purchase a Meade 5K HD-60 instead. For the one Meade (6.5mm) I had purchased, it too looked very good but much heavier. This did not exhibit this problem and was optically very god as well. Agena did offer to measure a sample or two from stock for comparison and to exchange the EP but without the certainty that a narrower thread would be found, decided to return it instead. I do feel Agena went out of their way to help with this issue and I will be happy to purchase from them again for the Meade as well as in the future.This review was provided courtesy of AgenaAstro.com
StarMike New Member
- Skill Level
- Unknown
- Time with Product
- Unknown
- User Notes:
- Review by starmike of Jacksonville, FL.
Dec 21, 2014Astronomy's best kept secret
Pros:Accurate,Easy to Use,Quality Lenses,Lightweight,Strong Construction,Compact
Cons: Comments:Since I purchased the 25mm, I have also added the 5, 8, 15mm units. I think this is one of the best kept secrets. The eyepieces are excellent. Pinpoint stars all the way to the edge and at 60 degree AFOV. They blow away my other eyepieces including my ES eyepieces. You won't be disappointed in these. If people tried these and word got out that you could get them at this price, Agena could not keep them in stock. Great job Agena!
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Oct 20, 2014Excellent oculars
Pros:Liberal Apparent Fov,Quality Lenses,Strong Construction
Cons: Comments:I spent a good amount of time and research looking for a new, high quality set of eyepieces to retire my older sets. I wanted a first-class, general purpose eyepiece that had a wide field for DSO and high contrast for planetary and binary stars. A difficult demand to fill at any price. I was prepared to spent more than twice the price for my final set.
Bottom Line: Would you recommend this item? Yes
Testing the Agena Dual ED 8mm against an 8mm brass Brandon and 7mm Parks under the severest binary star tests with a 6" refractor, the Agena proved to be of equal performance with the bonus of a much greater field of view. The field is absolutely flat and well corrected. The optical quality of the Agena met all my observational requirements.
This eyepiece immediately impressed me with its appearance, weight and design. Its "out of the box" quality promised good things to come and did not fail.
I am a serious observer of 35 years, a hard core refractor owner and demand the best in optics. The Agena Dual ED is a "dark horse" ocular that deserves high praise. You will NOT regret owning the Agena Dual ED eyepieces.This review was provided courtesy of AgenaAstro.com
Aug 18, 2014Excellent EP for the money
Pros:Low cost,Wide FOV
Cons: Comments:This is an excellent EP for the money. The 25mm gives me the same TFOV as my 32mm Plossl but at a higher magnification. I bought this for use with my Celestron 6SE.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jun 13, 2014Great wide field eyepiece
Pros:Accurate,Good Color Correction,Low Image Distortion,Quality Lenses
Cons:No Cons Until Now
Comments:Good wide field eyepiece with a reasonable price. Recommend it for DSO or as a finder eyepiece.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jan 25, 2014Great Value
Pros:Lightweight,Pinpoint Stars,Great Value
Cons: Comments:It is being used in a flip-mirror system to assist in centering astonomical targets for video and astrophotography. Perfect for this application.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Sort bySpecifications
Apparent Field of View 60° Barrel Size 1.25" (31.7mm) Bolt Case Included Yes - Free Agena Eyepiece Container Bolt Case Size Agena 52x80mm Coatings Fully Multi-Coated End Caps 2 Eye Relief by Design 20mm Filter Threads Standard 1.25" Filter Thread (M28.5 x 0.6) Focal Length 25mm Lens Elements 5 Lens Groups 3 Rubber Eye Guard Yes (Twist-Up Eyecup) Blackened Lens Edges Yes Manufacturer Agena AstroProducts Eyepiece Focal Length 20.1mm - 30mm Eyepiece Field of View 51 - 60 degrees Eyepiece Series Agena Dual ED Barrel Type With safety undercut Eyepiece Weight 5.90oz (167.26g)
