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.
Oct 31, 2018
Overall very good, only one complaintPros: Cons: Comments:
I have had the 4mm and 6mm version of this eyepiece for some time so I kinda knew what to expect. The 6mm is very good; this 7mm version is equally good except for having a bit more scatter (the halo around bright objects). But its still a very good value.
This review was provided courtesy of AgenaAstro.comMay 12, 2018
Good planetary eyepiecePros: Cons: Comments:
This review is for the 7mm.
The eyepiece was delivered in good condition and a little faster than expected. Thanks to Agena's service.
I just have a chance to test it with good seeing last night. The object is Jupiter and the scope is 90mm f/10 Achromat (at 128x). The image is clear, sharp with very good off-axis CA correction (much better than my stock 10mm plossl). Four cloud bands (with details in NEB and SEB) presented as well as the colorful GRS. No internal reflection was noticed.
Good value for the money.
This review was provided courtesy of AgenaAstro.com
joe1950 New Member
- Skill Level
- Time with Product
Mar 20, 2018
- User Notes:
- Review by JOSEPH D.
Excellent at a very good pricePros: Cons: Comments:
The BST line of eyepieces are excellent with sharp images, good contrast and low scatter. I've compared to other makes and they do well all the time. Lots of focal lengths to choose and all comfortable field of view and eye relief.
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 7mm Lens Elements 5 Lens Groups 3 Rubber Eye Guard Yes Blackened Lens Edges Yes Manufacturer BST Eyepiece Focal Length 5.1mm - 10mm Eyepiece Field of View 51 - 60 degrees Eyepiece Series BST UWA Planetary Barrel Type Tapered barrel Eyepiece Weight 4.90oz (138.91g)