WebJun 18, 2024 · The one I used stayed in collimation for months in a fixed position, piggybacked to my main scope, in my observatory. The secondary was the most vulnerable because of the thin spider so the 6" should be better because of the smaller diagonal and shorter spider arms but that's what you pay for having thin spider vanes. WebMy 13 inch f/3.0 RFT uses the same diagonal size as Coulter's original 13 inch f/4.5. An 18 inch scope calls for a diagonal to eyepiece distance of 12 inches, and if the mirror happens to be a f/4, then a 3 inch diagonal will work fine. This is a diagonal to primary ratio of 6:1. At this ratio, image degradation due to the diagonal obstruction ...
6 inch F5 refractor vs 6 inch F4 reflector - Cloudy Nights
WebAn included battery pack holds 8-AA batteries (user supplied), and this battery pack supplies power to the fans. The Apertura 10" Truss Newtonian OTA includes two Losmandy-style D-Series dovetails. Use one to mount the OTA onto your equatorial mount, and the other can ride on top and accept a guidescope, etc. Keep in mind that the this 10" f/4 ... WebUkuran F4 Alternative dalam satuan mm adalah 215 × 330 milimeter. Ukuran F4 Alternative dalam satuan cm adalah 21.5 × 33 centimeter. Ukuran F4 Alternative dalam satuan inci adalah 8.46 × 13 inci. Catatan: Kertas F4 banyak dipakai secara umum di seluruh dunia terutma di Asia Tenggara dan menjadi ukuran surat tulis untuk bisnis, perkantoran ... breakfast at radisson blu manchester airport
Exploring Low-Power Limits - Gary Seronik
WebMar 3, 2024 · F4 Paper Size in mm, cm, inch: F4 Size in mm is 210 × 330 millimeter. F4 Size in cm is 21 × 33 centimeter. F4 Size in inch is 8.27 × 13 inches. F4 Alternative Size in mm is 215 × 330 millimeter. F4 Alternative Size in cm is 21.5 × 33 centimeter. F4 Alternative Size in inch is 8.46 × 13 inches. WebJul 31, 2012 · Re: Ektar 12-inch F4.5. The 12" Kodak Ektar f4.5 is a Tessar copy of high quality. Should have a very nice look wide open at 4.5 and would be a nice portrait lens on 5x7-4x5 and at closer distances on 8x10. The Commercial Ektar is more like the Tessar IIb f6.3. While not as fast as the Ic the Tessar IIb was preferred by commercial … WebFocal ratio: f/4; Focal length: 600mm; Primary mirror: Parabolic primary mirror; minimum 92% reflectivity; protective quartz layer; Secondary mirror: 62.5mm minor axis; minimum … breakfast at port orleans french quarter