Outstanding Planetary and Lunar Eyepieces
These BST 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. Though primarily made for planetary observation, these eyepieces still excel when viewing deep sky objects.
More expensive eyepieces that have similar wide fields of view need many exotic glass elements to achieve that wide 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.
Each BST UWA Planetary eyepiece has 5 lens elements in 3 or 4 groups. These eyepieces provide high contrast, no scattered light, and the highest possible definition.
Comfortable Eye Relief
The eyepiece eye relief averages around 16mm for the entire series. The 25mm eyepiece features 20mm of eye relief. 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.
Please Note: While these eyepieces look similar to the TMB / TMB II ED eyepieces (and are also sold by some other sellers incorrectly under the TMB label), they are not the same as or copies of the 6-element TMB eyepieces. The factory making these eyepieces just uses the same external housing for the eyepieces.
Jun 21, 2018
Reasonable high power eyepiecePros: Cons: Comments:
I purchased this for my AT-60 travel scope so I would have a high-power eyepiece in the kit, and it performs quite well. It is, however, an excellent value - I compared it with my 2.5mm Type 6 Nagler and while the Nagler is definitely in a different class (better contrast and acuity), the Nagler is also some five times the price, so one would hope to see a difference. But for most users, the difference would not warrant the huge price difference.
This review was provided courtesy of AgenaAstro.comMar 7, 2018
BST 1.25" 58-deg UWA Planetary Eyepiece - 2.5mmPros: Cons: Comments:
This is an awesome planetary eyepiece for the price. I have viewed the moon with my WO GT71 with excellent results. There is some CA and vignetting on the edge, but this is to be expected with this price range.
This review was provided courtesy of AgenaAstro.comOct 20, 2014
I was looking to update and unify my working eyepieces by retiring three older specialized sets, and find one set that would be more versatile. These would have to have a high degree of resolution for binaries, high contrast for planetary work, and a comfortable wide field for deep sky work.
After months of reading and researching, I actually stumbled onto Agena's impressive lineup of oculars. The BST Ultra Wide Planetary eyepieces are extremely flat across their field with excellent color correction. The eye lens is incredibly large. No pinholes here even at 2.5mm!
The apparent field of view is spacious for deep sky work. The resolution excellent for binary star busting. And the high contrast is great for planetary study. All this is accomplished with just 5 lenses in 3 groups so they do not rob me of light.
The feel and build quality is excellent. They are impressive just to look at. I bought the whole series and am delighted with their performance with my 3" & 4" Unitrons and 6" AVX refractor. These are a tremendous value. Do not let the low price deceive you!
This review was provided courtesy of AgenaAstro.comSort by
Apparent Field of View 58° 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 16.5mm Filter Threads Standard 1.25" Filter Thread (M28.5 x 0.6) Focal Length 2.50mm Lens Elements 5 Lens Groups 3 Rubber Eye Guard Yes Blackened Lens Edges Yes Manufacturer BST Eyepiece Focal Length 5mm and Under Eyepiece Field of View 51 - 60 degrees Eyepiece Series BST UWA Planetary Barrel Type Tapered barrel Eyepiece Weight 5.50oz (155.92g)