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BST 1.25" Flat Field Eyepiece - 27mm

4.3 (3 Reviews) Read Reviews Write Review
Brand BST
Part Number E-BS-FF27
Availability available

Product Info

Manufacturer Description

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.

Reviews

4.3 (Based on 3 Reviews) 100% of reviewers recommended this product.
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    1. Guest

      Skill Level
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      Time with Product
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      User Notes:
      Review by Bernie L.
      1545838844
      Dec 26, 2018

      4.0 Good Eyepiece

      Pros:

      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.

      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 Dude of California.
      1474934400
      Sep 26, 2016

      4.0 Great eyepiece, but heavy

      Pros:

      Accurate,Strong Construction,Quality Lenses

      Cons:

      Heavy

      Comments:

      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.

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

      This review was provided courtesy of AgenaAstro.com

    3. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by David of Jerusalem, Israel.
      1453593600
      Jan 23, 2016

      5.0 Good price, good eyepiece

      Pros:

      Quality Lenses

      Cons:

      Comments:

      Great optics, flat and crisp field from edge to edge. Good price, with quality of the top-of-the-line brands.

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

      This review was provided courtesy of AgenaAstro.com

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      Specifications

      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)