Concept: In 1979, I had to sacrifice size, cost and weight in the original Nagler design to
achieve what were previously mutually exclusive interests; extremely wide field, full field
sharpness and comfortable eye-relief. Fortunately, users agreed that a lifetime of "spacewalk"
viewing pleasure justified the investment. Fast forward to 1999. As the hobbyist population
ages (along with me), more amateurs need eyeglasses. It was time to adjust the mix of
parameters for observers who require or prefer long eye-relief. Under the framework of the
"Nagler" design, the new field was set at 60° with a uniform 20mm eye-relief. Optimizing this
new design with fully multicoated exotic glasses, we reached our new goal of full field
sharpness with true orthoscopic linearity, highest contrast for critical planetary viewing, and
compact size. The size and weight blend also makes the Radian preferable for small
instruments and bino-viewers, and allows the convenience of being parfocal with other 1¼"
Tele Vue eyepieces. - Al Nagler
Tele Vue Radian Eyepieces.

"What sets Radians apart from other long eye-relief, short-focal-length eyepieces is superb
image quality. Even discerning planetary observers who customarily choose Plössl or
orthoscopic designs are switching to Radian." — Sky & Telescope, December 1999

Instadjust was developed for maximizing contrast while aiding in proper eye positioning for
non-eyeglass wearers. It is essential, since with the Radian's long eye-relief, non-eyeglass
wearers could easily get too close to the eyepiece, resulting in vignetting where edge field
rays miss your pupil. The push-pull, click-stop adjustment permits fast positioning and
maximum suppression of environmental stray light.

Another unique development is the Pupil Guide. It helps non-eyeglass wearers, especially
novices, zero-in and stay centered on the exit pupil. The Pupil Guide is included with all
Radian and Nagler Type 4s and fits under the soft, fold-down rubber eyeguard.

Prices:
ERD-18.0 - 18.0 Radian - £162.00
ERD-14.0 - 14.0 Radian - £162.00
ERD-12.0 - 12.0 Radian - £162.00
ERD-10.0 - 10.0 Radian - £162.00
ERD-08.0 - 8.0 Radian - £162.00
ERD-06.0 - 6.0 Radian - £162.00
ERD-05.0 - 5.0 Radian - £162.00
ERD-04.0 - 4.0 Radian - £162.00
ERD-03.0 - 3.0 Radian - £162.00

The Astronomy Shop

1 Tone Hill. Wellington

Somerset TA21 0AU

United Kingdom

Telephone: +44 (0)1823 665510