BST 1.25" Flat Field Eyepiece - 27mm
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- 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
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.
Please note: The cosmetic appearance/labeling of this item changes often and may not exactly match what's shown in the photos above. Hence, multiple eyepieces you order may not match others in that same order or previous ones you may have purchased.
| Free Shipping Graphic | Free US Shipping |
|---|---|
| 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 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 |
| Hide Found a better Shipped Price on Frontend? | No |
- 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
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.
Please note: The cosmetic appearance/labeling of this item changes often and may not exactly match what's shown in the photos above. Hence, multiple eyepieces you order may not match others in that same order or previous ones you may have purchased.
| Free Shipping Graphic | Free US Shipping |
|---|---|
| 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 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 |
| Hide Found a better Shipped Price on Frontend? | No |
BST 1.25" Flat Field Eyepiece - 27mm