Re: [APML] NGC 6914 Tech Pan Tri-color and CCD comparison

["Mike Cook, AF9Y" <mwcook@concentric.net>]

You might want to take a look at a full size section around the
reflection nebula:

http://www.webcom.com/af9y/ngc6914crp.htm

Notice that even though the Tech Pan is shot at F/8 and the CCD at F/5.4,
the resolution and star sizes are nearly identical.  If anything, the CCD image
has the better resolution.   This is not what you would expect.  Chuck and
I have discussed it and he feels that the red focus might not be as good in this
shot as some of his other Tri-Color shots.  Indeed, if you compare only
the blue and green channels, the resolution is even closer to the CCD.


Date sent:      	Wed, 31 Oct 2001 12:38:48 +0100
From:           	Thomas Langthaler <Thomas.Langthaler@lms-gmbh.de>
Organization:   	LMS
To:             	astro-photo@seds.org
Subject:        	Re: [APML] NGC 6914  Tech Pan Tri-color and CCD comparison
Send reply to:  	astro-photo@seds.org

> Rob, Bobby,
> 
> you have to take into account, that both images have been taken at
> different f/ratios. Just to correct the exposure ratios:
> 
> CCD: 3*6 + 3*6 + 3*10 = 66 min at f/5.4
> 
> TP: 3*180 = 540 min at f/8
> 
> Hence the real factor between both is 540/66 * (5.4/8)**2 = 3.73, which
> is considerably less than 10, but impressive anyway.
> 
> Thomas
> 
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Mike Cook, AF9Y
http://www.webcom.com/af9y
mwcook@cris.com




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