bettershot
Nagler
82° Apparent Field Eyepieces
TeleVue.com: Eyepieces > Nagler > 31mm
31-mm
Model #EN5-31.0
Focal Length (mm)31
Barrel Size (in.)2"
Apparent Field of View (deg.)82
Eye Relief (mm)19
Weight (lb / oz)2.20 / 35.2
Field Stop (mm)42
Compare to similar focal lengths


Related Links

With the 31mm, the unique 6-element design using four exotic glasses, maintains the contrast advancement of the Type 4s while achieving a true field area 82% larger than the 22mm Type 4! Owners of fast Dobsonian/Newtonians can enjoy a larger true field, free of secondary shadowing, than ever before. For example, a 12.5", f/4.5 scope with a Paracorr will deliver a 1.5 degree field (3 Moon diameters), at 53x with a 6mm exit pupil. Use our eyepiece calculator to figure out what the 31mm will deliver on your scope.

Why Are There 3 Types of Naglers?

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.


Copyright © 2003-2024 Tele Vue Optics, Inc., 32 Elkay Dr, Chester, NY, 10918 · Call for advice: 1-845-469-4551 (9am-4:30pm ET) · TeleVue.com · Privacy Policy