Technical Specifications
Model number: EN5-31.0
Focal Lenght: 31 mm
Barrel Size: 2″
Apparent Field of view: 82°
Eye Relief: 19 mm
Weight: 2.2 lb
Field Stop: 42 mm
We Have it in Stock? We're on it, shipping your order on the same day. *(Ordered before 1PM & Business Hours only)
If the item is unavailable: It may be in transit to us or on order with the supplier. If not, we will promptly place the order. In case of delays, we will keep you informed.
With the Tele Vue Nagler 31mm Type 5, 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.
82° Apparent Field Eyepieces
Concept: You may know there’s a long history of naming eyepieces after their designers: Kellner, Erfle and Plossl, to name a few. In the late 70’s I designed an eyepiece sufficiently radical that I dared attach my name to it. Even today, I must admit a little discomfort when talking about “Nagler” eyepieces.
With “Naglers”, my aim is to approach the wide angle perspective of naked eye vision, while maintaining the highest degree of sharpness, contrast, and viewing comfort. The goal is to allow the telescope to virtually “disappear,” leaving the impact of “spacewalk” viewing. — Al Nagler
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 18mm of eye relief and with the “instajust” eyeguard are best for eyeglass wearers or Dioptrx users in their 22, 17, 12mm focal length range.
Take a “spacewalk” across a wide, sharp 82° apparent field
Compare a penny to a half dollar to see the relative size between a 50° and 82° apparent field – almost 3 times the area difference! And while others boast of impressive apparent field sizes, Tele Vue’s philosophy of “showing no field unless it’s fine” stresses full field image quality as the ingredient for impressive views. Blackened lens edges, anti-reflection threads and rubber eyeguards deliver maximum contrast. Adapter skirts for 2″ focusers on larger 1¼” models and rubber grip rings are additional Tele Vue “firsts”. Even 2″/1¼” barrel models have an additional feature allowing the 2″ extension tube (EBX-2120) to be screwed on, which permits use of 2″ filters as well as 1¼”. 100% full field visual inspection on our own flat-field test instruments guarantees the performance of every Tele Vue eyepiece.
Model number: EN5-31.0
Focal Lenght: 31 mm
Barrel Size: 2″
Apparent Field of view: 82°
Eye Relief: 19 mm
Weight: 2.2 lb
Field Stop: 42 mm