Re: Fog Flats

[hjohnson@pluto.njcc.com (Herbert R Johnson)]

On Sat, 23 Sep 2000 23:33:29 -0500, Tom Droege <tdroege@veriomail.com> wrote:
*>I am frustrated since I only have low clouds/fog to look at.  I used this 
*>opportunity to try to test the gain and noise of the modified cameras.  The 
*>results:
*>
*>V camera  gain = 2.8 e- / ADU  noise = 17.4 e-
*>I  camera  gain = 2.5 e- / ADU  noise =  19.7 e-
*>
*>OK, the fog flats were not very flat.  It was hard to get a reasonable 
*>exposure.  The flats were 400 counts for the V camera and 3000 for the I 
*>camera.  One would like (I think) close to half full scale.  The numbers 
*>are quite similar to the last time I did this.  I guess that means that I 
*>have done no damage.  We shall see.
*>
*>Tom Droege

Can you (and Arne) also confirm the saturation values for your cameras?
Tom, maybe you can plot exposure time vs average for your "fog flats"
and see if any obvious knee appears. If your flats are reasonably flat
you need only post sample numbers rather than whole images for further
analysis by other TASS members - it certainly would take less disk
space and download time to do so.

I certainly appreciate calibration data, Tom, so I encourage your efforts
on this. In my prior work with radio astronomy data (collected for SETI)
old calibration data allowed for better estimates and review of data collected
ten and twenty years later, and re-analized ANOTHER 20 years later. So
keep posting your calibration and testing results.

Herb Johnson

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