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 Post subject: Optics Advice Please
PostPosted: Mon Nov 21, 2016 6:32 pm 
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Joined: Sat May 02, 2009 2:37 pm
Posts: 158
Hi All,

Could someone provide (or suggest a link to) a really straightforward layman's explanation about optics, including the relationship between focal length and field of view?

Thanks in Advance,

Geoff


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 Post subject: Re: Optics Advice Please
PostPosted: Mon Nov 21, 2016 10:01 pm 
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Joined: Mon Jan 18, 2010 9:25 am
Posts: 5298
Hi Geoff.
The AFOV, apparent FOV, depends only on the type of eyepiece.
45 to 50 deg Plossl
WA 60 to 65 deg, say Erfle type.
EWA 65 to 82 deg plus.

The real FOV is simply the AFOV divided by the magnification.

The magnification is the objective focal length divided by eyepiece fl.

Regards,
David


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