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David Nagler Eyepieces Video Interview
David Nagler was a guest on Deep Astronomy channel's "Telescope Talk Hangout" show withhost Tony Darnell. In this hour-long show he discusses how eyepieces work, eye-relief, real field, apparent field, magnification, exit pupil, seeing, personal factors that impact eyepiece choice, Nagler eyepiece evolution, Tele Vue quality control and more.

Index to Video
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0:02:40 Tony Darnell introduces David Nagler
0:03:38 What an eyepiece does more info
0:08:00 Eyepiece characteristics (eye relief, apparent field of view, true field of view, and field stop) and magnification
0:17:38 Usable magnification
0:20:30 The "Majesty Factor" (relationship between magnification, apparent field of view, and contrast) more info
0:23:24 Exit pupil and eye relief (including reflector/refractor considerations)
0:29:57 Magnification (atmospheric defocusing)
0:35:55 Eyepiece recommendations (magnification, true field of view, and design considerations) more info
0:42:28 Differences between Nagler eyepiece types
0:47:39 Discontinued eyepieces (Nagler Original, Type-2, and Wide Field series)
0:49:26 Spacewalk experience
0:51:08 Tele Vue (engineering, fast and slow f-ratio quality control, improvements, and business relationships) more info
0:57:00 Parfocal Nagler Planetary Zoom eyepiece more info
0:58:10 Bino Vue binocular viewing more info
0:59:52 Observing at the eyepiece
1:02:05 Telescope focusing

Screen capture of Da...
Screen capture of David from the show.