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Many amateurs need eyeglasses to correct astigmatism. Several companies have already borrowed the "Nagler" concept of integrating a "barlow" lens assembly with a longer focal length lens group to produce very short focal eyepieces with very long eye-relief to satisfy eyeglass wearers. It's now time for Tele Vue to revisit the trade-off of field versus eye-relief.
By limiting the field to 60 deg. (a Radian = 57.3 deg.) and establishing a uniform 20mm eye-relief, TeleVue reworked the Nagler concept using the latest glass types to achieve optimum full field sharpness, freedom from distortion, freedom from ghosting (for critical planetary viewing) along with a unique adjustable eyeguard assembly which called "Instadjust."
Instadjust was developed from the need for proper eye position for non-eyeglass wearers. It is essential, since with Radian's long eye-relief, non-eyeglass wearers would easily tend to get too close to the eyepiece, resulting in vignetting the field, just as you would moving out from the exit pupil. The click-stop, Instadjust eyeguard permits fast, accurate positioning of the eye to the exit-pupil with maximum suppression of environmental stray light. Instadjust is topped off by a soft (for comfort and eyeglass protection) fold-down rubber eyeguard and protective cap.
Usual Tele Vue features such as full multicoating, blackened lens edges, parfocalization, and grip-ring complement the Radian line. With a reasonable size, weight and cost, the Radians will set a new benchmark in viewing pleasure for any person and any target within the eyepiece focal length range of 3mm-18mm. 18, 14, 12, 10, 8mm models have just 6-elements. 6, 5, 4, 3mm have 7 elements.
- Focal Length: 6mm
- Apparent Field: 60°
- Barrel Size: 1.25"
- Eye Relief: 20mm
- Field Stop: 6.3mm
- Weight: 0.79 lbs / 12.6 oz
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