82° Apparent Field Eyepieces
|TeleVue.com: Eyepieces > Nagler > EP_EN5-26.0|
|Focal Length (mm)||26|
|Barrel Size (in.)||2"|
|Apparent Field of View (deg.)||82|
|Eye Relief (mm)||16|
|Weight (lb / oz)||1.60 / 25.6|
|Field Stop (mm)||35|
|Compare to similar focal lengths|
This is a somewhat smaller, lighter and more powerful version of the celebrated 31 Nagler Type 5. Why? Because customers such as Tom Dietz, from the Smithsonian, are pests! :-) It weighs about 1.6 lbs and has a field stop diameter of 35mm. It is parfocal with the 17mm Nagler Type 4, making it a nice match in size, weight and convenience.
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.