Standard eyepieces provide sharp, pinpoint star images at the center of the field but as you look out toward the edges, stars often begin to get blurred and out of focus. Eliminating this distortion usually calls for expensive optical designs with additional lens elements to eliminate the field curvature. But these new BST eyepieces use a 5 or 6 element design that offers a flat field over the entire field of view at an attractive price.
Featuring large eye lenses, wide fields of view (from 53°-65°), and generous eye relief (from 9.6mm-24.4mm), these eyepieces are a pleasure to use. Fully multicoated lenses maximize light transmission and edge blackening of all lens elements ensures excellent contrast. Other features include safety recess grooves on the 1.25" barrels, standard 1.25" filter threads, and twist-up eyecups.
Dec 26, 2018
Good EyepiecePros: Cons: Comments:
Good build. I bought the complete set to use with my William Optics Z61. The stars are sharp almost to the edge which is amazing with such a fast scope. This eyepiece has some flaring with brighter stars that the rest of the set does not exhibit, also a bit of oil or grease was on the top glass from the twist up eyecup - hence the 4 stars.
This review was provided courtesy of AgenaAstro.comSep 26, 2016
Great eyepiece, but heavyPros:
Accurate,Strong Construction,Quality LensesCons:
I have a similar eyepiece. It works great, but it weighs 6.5 oz. It's a bit too heavy for my 70mm refractor on a lightweight tripod with an Alt/AZ yoke mount. Ok for a larger Dobsonian scope though.
This review was provided courtesy of AgenaAstro.comSort by
Apparent Field of View 53° Barrel Size 1.25" (31.7mm) Bolt Case Included Yes - Free Agena Eyepiece Container Bolt Case Size Agena 52x80mm Coatings Fully Multi-Coated Height (with Eye Guard) 2.91" (74.0mm) Max Width 1.82" (46.3mm) End Caps 2 Eye Lens Diameter 1.07" (27.1mm) Eye Relief by Design 23.0mm Field Stop Diameter 24.4mm / 0.96" Filter Threads Standard 1.25" Filter Thread (M28.5 x 0.6) Focal Length 27mm Lens Elements 5 Lens Groups 4 Rubber Eye Guard Yes Blackened Lens Edges Yes Manufacturer BST Eyepiece Focal Length 20.1mm - 30mm Eyepiece Field of View 51 - 60 degrees Eyepiece Series BST Flat Field Barrel Type With safety undercut Eyepiece Weight 6.50oz (184.27g)