The Tele Vue 20mm Type 5 Nagler eyepiece is a compact 1-pound, 2" eyepiece that fills out the eyepiece line and is a worthy successor to the heaviest commercial eyepiece ever produced: the Nagler 20mm Type 2, which weighed-in at 2.3-lb. when introduced in 1986.
All Tele Vue Nagler eyepieces have proprietary tuned full multi-coatings, blackened lens edges, high index glasses, fold-down eyeguards, rubber grip rings, cover for the eyeguard, an undercut in the barrel for extra locking security, and filter threads. All Tele Vue eyepiece lines are proprietary, in-house designs manufactured to their specifications and tolerances. Every eyepiece is individually tested at Tele Vue to ensure it meets high optical and cosmetic standards.
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, sold separately) to be screwed on, which permits use of 2" filters as well as 1¼". 100% full field visual inspection on TeleVue's flat-field test instruments guarantees the performance of every Tele Vue eyepiece.
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
The Type-5 permits the largest true field possible (31mm has 42mm field stop), while the shorter focal length Type-6 models 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, 12mmfocal length range.
|Apparent Field of View||82°|
|Barrel Size||2" (50.8mm)|
|Bolt Case Included||Yes - Free Agena Eyepiece Container|
|Bolt Case Size||Agena 65x80mm|
|Max Width||2.1" (53.3mm)|
|Eye Relief by Design||12mm|
|Field Stop Diameter||27.4mm|
|Filter Threads||Standard 2" Filter Thread (M48 x 0.75)|
|Rubber Eye Guard||Yes|
|Blackened Lens Edges||Yes|
- Suitable for use with Tele Vue Dioptrx / digiscoping
|Eyepiece Focal Length||15.1mm - 20mm|
|Eyepiece Field of View||Over 80 degrees|
|Eyepiece Series||Tele Vue Nagler|
|Barrel Type||With safety undercut|
|Eyepiece Weight||16.60oz (470.60g)|