Re: [APML] Dynamic Range of CCD

[Matt BenDaniel <matt@starmatt.com>]

At 05:09 PM 4/5/2002 -0600, Gene Horr wrote:
>Matt BenDaniel wrote:
>
>> Stars, my man, stars use up dynamic range. 
>
>But we aren't talking about stars.  I am talking about your average galaxy
>or nebula.  This was specifically stated.  Although it wasn't specifically 
>stated, I am also only referring to "pretty pictures", not photometry.  
>
>If the data for the DSO is in the range of 500 - 1,000 counts ADU it isn't
>going to matter a whole lot to the stars in the final image if you do 
>your top end cutoff at 1,000 or 5,000.  For real world use the data
>you are trying to get is in that 500 count range.

Gene,

You can't see the nice pretty picture of a galaxy if star blooms are stomping all over it. That is the biggest reason why you need dynamic range (with NABG). The ADU counts from the brightest stars will be near or at the max (e.g. 65,000). You cannot put little black stickers on the ccd chip where the bright stars are. What matters is not the dynamic range of an isolated object; it is the dynamic range over the entire field of view that matters.
--
Matt BenDaniel
matt@starmatt.com
http://starmatt.com


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