82° Apparent Field Eyepieces
|TeleVue.com: Eyepieces > Nagler > EP_EN4-17.0|
|Focal Length (mm)||17|
|Barrel Size (in.)||2"|
|Apparent Field of View (deg.)||82|
|Eye Relief (mm)||17|
|Weight (lb / oz)||1.60 / 25.6|
|Field Stop (mm)||24.3|
|Compare to similar focal lengths|
Applying the experience of the Radian development to the 82° Nagler series, yielded more contrast, reduced pincushion, more true field, and longer eye-relief. With added eye-relief, the click-stop Instadjust eyeguard helps maintain proper eye distance and centration.
For deep sky viewing, the comfort, clarity and contrast gets us closer to our "spacewalk" viewing goal.
To achieve the full magnification range over 82° apparent field of view requires two types: Nagler Type-5 with focal lengths of 31, 16mm and Nagler Type-6 with focal lengths of 13, 11, 9, 7, 5, 3.5, 2.5mm.
The Type-5 permits the largest true field possible (31mm has 42mm field stop).
Type-6 models have shorter focal lengths, are parfocal, with similiar size and weight, and all with a comfortable 12mm eye relief.
The Type-4 models feature about long eye relief and with the "instajust" eyeguard are best for eyeglass wearers or Dioptrx users.