BST 1.25" Flat Field Eyepiece - 27mm

Our Price: $69.00
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Our Product ID: E-BS-FF27
Manufacturer SKU: E-BS-FF27
Item Can Ship: Worldwide
BST 1.25" Flat Field Eyepiece - 27mm

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  • BST 1.25" Flat Field Eyepiece - 27mm
  • BST 1.25" Flat Field Eyepiece - 27mm
  • BST 1.25" Flat Field Eyepiece - 27mm
  • BST Flat Field Eyepieces with Eyecups Retracted
  • BST Flat Field Eyepieces with Eyecups Extended

Website Special - FREE Agena plastic bolt case / storage container included with this eyepiece (a $4.50 value)!

Quick Overview

  • Optical design includes 5 or 6 elements to nearly eliminate field curvature distortion
  • Eliminates out of focus stars near the edge of the field of view
  • Feature large eye lenses and generous eye relief - from 9.6mm-24.4mm
  • Wide fields of view – from 53° to 65°
  • Fully multi-coated with blackened edges on all lens elements
  • 1.25” barrels and standard 1.25” filter threads
  • Twist-up eyecups and dust caps included

Product Details

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.

Eyepiece Series FF (Flat Field)
Focal Length 27mm
Barrel Size 1.25" (31.7mm)
Apparent Field of View (Mfg Specified) 53°
Eye Relief (Designed) 23.0mm
Filter Threads Standard 1.25" Filter Thread (M28.5 x 0.6)
Coatings Fully Multi-Coated
Lens Elements 5
Lens Groups 4
Blackened Lens Edges Yes
Barrel Safety Recess Yes
Barrel Type With safety undercut
Protective Plastic Storage Container Yes - Free Agena Eyepiece Container
Protective Plastic Storage Container Size Agena 52x80mm
Height (With Eyeguard Extended) 2.91" (74.0mm)
Maximum Width 1.82" (46.3mm)
End Caps 2
Eye Lens Diameter 1.07" (27.1mm)
Field Stop Diameter 24.4mm / 0.96"
Rubber Eye Guard Yes
Weight 6.5 oz (184 g)
Country of Manufacture China

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