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Old 07-02-2014, 09:55 PM
rally
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Join Date: Sep 2007
Location: Australia
Posts: 896
Ray,

MaxIm and CCDsoft both add 100 to each pixel in the image at the time of acquisition - its not part of any calibration. (Mira is different)

I still think the ideal exposure times are very dependent on what you are trying to achieve and level of detail in your chosen target, as opposed to purely the maths of the CCD and sky background.

If you are trying to capture really faint detail, (or lack of light - eg dark dust cloud structure) then there is no substitute for long exposure.
If the photon count is so low per minute or per hour, then it will be so low as to be buried within the read noise if the exposure time is short.
A longer exposure time is still required to get that data up and out of the noise, but also to bring it up to levels that arent going to suffer from quantisation problems during post processing.
That is where I think that a single exposure time isnt going to be able to provide the same level of high dynamic range information as multiple stacked exposures of varied times and combined together.

Rally
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