Tele Vue 22mm Nagler Type 4 Eyepiece
TeleVue Nagler Eyepieces
"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 '70s 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
Compare a penny to a half dollar to see the relative size between a 50 degree and 82 degree 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 inch focusers on larger 1.25 inch models (12mm Nagler Type 4 and 22mm Panoptic) and rubber grip rings are additional Tele Vue "firsts". Even 2 inch/1.25 inch barrel models have an additional feature allowing the 2 inch extension tube (EBX-2120) to be screwed on, which permits use of 2 inch filters as well as 1.25 inch. 100% full field visual inspection on our own flat-field test instruments guarantees the performance of every Tele Vue eyepiece.
Televue Nagler Type 4 Eyepieces: Applying the experience of the Radian development to the 82 degree Nagler series, yielded more contrast, reduced pincushion, more true field, longer eye-relief, and fewer elements to achieve focal lengths of 12mm, 17mm and 22mm. With added eye-relief, the click-stop Instadjust eyeguard helps maintain proper eye distance and centration. When TeleVue designed the Radian series of eyepieces, they used the Nagler concept as the basis. However with the Radians, the decided to balance size, weight, and cost relative to a consistent 20mm eye relief. During the design process they found they could not only balance these factors for 1.25 inch focusers, but new glass types lead to better imaging, contrast enhancement, reduced pincushion, ghost suppression, and a new concept in a click-stop adjustable eyeguard as well.
Applying that experience to the 82 degree, Nagler Type 2 design goals would potentially provide increased eye-relief, more contrast, reduced pincushion, and more true field as well. The first Nagler Type 4 to arrive is the 12mm version, replacing not only the 12mm Nagler Type 2 but its predecessor 13mm (the first Nagler) and the 11mm, now considered a collector item. Users confirm that for deep sky viewing, the comfort, clarity and contrast of the 12mm Type 4 gets Tele Vue closer to their "spacewalk" viewing goal. Similar in size and weight to Type 2, it has more true field and 50% greater eye relief, while using just six elements.
OPT Product Number: TE-EN4-22.0
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