Exit Pupil Vs. Aperture
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- AntennaGuy Online
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Re: Exit Pupil Vs. Aperture
* Celestron C6 SCT on a Twilight 1 Alt-Az mount
Prof. Barnhardt to Klaatu in The Day the Earth Stood Still: "There are several thousand questions I'd like to ask you.”
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Re: Exit Pupil Vs. Aperture
Mounts: SW: SkyTee2, AzGTi; iOptron: AZMP; ES: Twilight I; Bresser: EXOS2; UA: MicroStar.
Binos: APM: 100-90 APO; Canon: IS 15x50; Orion: Binoviewer, LG II 15x70, WV 10x50, Nikon: AE 16x50, 10x50, 8x40.
EPs: Pentax: XWs & XFs; TeleVue: Delites, Delos, Panoptic & Plossls; ES: 68, 62; Vixen: SLVs; Baader: BCOs, Aspherics, Mark IV.
Diagonals: Baader: BBHS mirror, Zeiss Spec T2 prism, Clicklock dielectric; TeleVue: Evebrite dielectric; AltairAstro: 2" prism.
Filters: Lumicon: DeepSky, UHC, OIII, H-beta; Baader: Moon & SkyGlow, Contrast Booster, UHC-S, 6-color set; Astronomik: UHC.
Solar: HA: Lunt 50mm single stack, W/L: Meade Herschel wedge.
Observing: DSOs: 3122 (Completed: Messier, Herschel 1, 2, 3. In progress: H2,500: 2196, S110: 77). Doubles: 2461, Comets: 34, Asteroids: 261
- notFritzArgelander
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Re: Exit Pupil Vs. Aperture
- DeanD
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Re: Exit Pupil Vs. Aperture
It depends what you want the binos for: 7x50 with 7mm exit pupil will give you a bright image for sure, but a lot of objects will be next to invisible because the background sky will be too bright and the objects are too small. Contrast, surface brightness and object size will determine how well you see a lot of
Most of us don't have 7mm pupils any more either: so some light is wasted and you might find that 7mm exit pupils give you no "brighter" view than 5mm, especially in suburban skies when your eyes can't fully dark adapt.
A lot of expert bino observers will tell you that an easy way to determine a binocular's over-all suitability for astro viewing is to multiply the magnification by the objective lens diameter. Usually, the higher the number the better. 7x50's give you 350, while 11x70's give 770, 25x100's give 2500, etc. (Mind you, the naked eye view gives a number of 1x7=7 (maximum): so any binocular will give you amazing views compared to nothing at all!!!)
As for telescopes and eyepieces there are lots of factors involved, and no one instrument is suitable for everything...
Many people enjoy the portability of binoculars and hand-holding, but of course the higher the power and the larger the binocular the harder this becomes.
There are lots of articles, books, and discussions out there about all this, so that is enough from me for now!
All the best,
Dean
Binos: Steiner Wildlife XP 10x26, Swarovski 8x30 Habicht, Zeiss SFL 8x40, Vanguard Endeavour 10.5x45, Fuji FMTR-SX 10x50, Tak 22x60, Orion Resolux 15x70
Eyepieces: way too many (is that possible?), but I do like my TV 32mm plossl, 13mm Nagler T6, 27mm Panoptic and 3-6mm Nagler zoom, plus Fujiyama 18mm and 25mm orthos and Tak 7.5mm LE
- russmax
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Re: Exit Pupil Vs. Aperture
--Russmax
Celestron AVX 8" SCT & Omni XLT 102 AZ
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