Atik Cameras

Author Topic: Standard Deviation for 11k bias frame?  (Read 11700 times)

snovosel

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Standard Deviation for 11k bias frame?
« on: March 28, 2012, 12:13:12 pm »
Does anyone know what the standard deviation is supposed to be for a bias frame on the 11k? I sent this question to Atik "Support" a week ago but have not heard back from anyone yet, so I figured this method may be faster.

Thanks

SteveNj

snovosel

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Re: Standard Deviation for 11k bias frame?
« Reply #1 on: April 12, 2012, 07:54:12 pm »
No one knows??  :o

Konihlav

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Re: Standard Deviation for 11k bias frame?
« Reply #2 on: April 13, 2012, 07:51:29 am »
I know only that it will be strongly dependent on CCD chamber temperature. KAI-11002ME has huge (biggest I've ever seen) field non-linearity so a bias at -40 degrees Celsius looks like a bias fron Sony CCD at -10 deg C.

The only thing I could do for you is to measure gain and readout noise of your CCD camera, if you cool it down to as much as you can and take a series of bias frames and couple of flat field frames (no matter which filter or how big vignetting you get, any usable flat field that you normally use for data calibration).

see something on my blog
Pavel



http://blog.astrofotky.cz/pavelpech/

snovosel

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Re: Standard Deviation for 11k bias frame?
« Reply #3 on: April 13, 2012, 02:36:01 pm »
Pavel, are you absolutely certain that a bias frame standard deviation assessment is not independent of, and will vary based on, different chamber temps?

Steve



Konihlav

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Re: Standard Deviation for 11k bias frame?
« Reply #4 on: April 13, 2012, 03:29:48 pm »
sure, like 1+1 is supposed to be 2. Check my blog. It's all about precision with which you want the answer.
« Last Edit: April 13, 2012, 03:31:34 pm by Konihlav »

snovosel

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Re: Standard Deviation for 11k bias frame?
« Reply #5 on: April 13, 2012, 06:15:29 pm »
Ah, got it.  :P

Great blog by the way! Many thanks Pavel!!