Re: [APML] OT: CCD integration times.

["Jim Janusz" <jjanusz@dc.rr.com>]

Hi Jason,

For a good discussion on signal to noise vs. exposure times take a look at
this article;

Sub-Exposures and Signal-to-Noise Considerations (5/9/2004):

On this page;

http://www.hiddenloft.darkhorizons.org/notes/acq.htm

As to methods of combining images, median and sigma combines do a good job
of reducing noise in images when you have sufficient signal, i.e. many
exposures of adequate length to bring the signal up out of the noise.
Sometime you do both on all sub exposures and combine them.  There does not
seem to be one right way to do this and it mainly depends on the quality of
the data.

Coming over to the dark side are you?  (G)

Jim

----- Original Message ----- 
From: "Jason Ware" <jtw@galaxyphoto.com>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Thursday, October 28, 2004 9:13 PM
Subject: [APML] OT: CCD integration times.


>
>
> Robert and others. Something I just don't get about
> CCD imaging after reading several articles and books.
>
> Lets say you do 30 x 1 minutes, or 5 x 6 minutes, or
> what ever. I know that if you do, say 3 x 10 minutes,
> you would median combine, but what about the 3 x 1 minute?
> Would you add? Would you add a half and median combine
> with the other half? I don't understand the tradeoffs.
>
> -- 
>  -Jason Ware
>
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