Re: [APML] Question on vignetting

[Duncan Munro <dmunro@sfu.ca>]

It's probably a combination of several factors.  It's just too bad they 
don't make larger aperture R/Cs. There's an excellent article here on 
R/C back focal distance and off axis aberations:

http://www.ziplink.net/~lester/flr-notes.html


cheers

Duncan



Bradley wrote:

>Thanks, Duncan;
>
>Looks like yours is a little less than what I'm seeing with mine. Could that
>be a result of the reduced distance of film plane from FR and/or rear cell
>(looks like your film plane is closer both to FR and rear cell, actually)?
>
>Clear, dark and steady skies
>
>Bradley
>
>Thorn Garden Observatory
>http://astronomy.thorngarden.net
>
>----- Original Message ----- 
>From: "Duncan Munro" <dmunro@sfu.ca>
>To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
>Sent: Tuesday, March 15, 2005 10:17 AM
>Subject: Re: [APML] Question on vignetting
>
>
>  
>
>>I have a sample of vignetting with a f6.3 R/C and a 10" Meade here:
>>
>>http://www.sfu.ca/%7Edmunro/essay.html
>>
>>you can't hope to fill a 35mm frame but you should be able to almost
>>fill a DSLR frame.
>>
>>cheers
>>
>>Duncan
>>    
>>
>
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>  
>

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