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let's talk dark libraries on cooled cameras
So now I've got a cooled CCD camera. There's clouds here for the next week, so thinking I can build up a dark library. I never bothered with the 40D and took darks every outing. But since the temperature can be regulated now, why not? Some questions and thoughts I'm having:
What min and max temperatures? I understand (yet to test myself) that the QSI583 can get down to around -20 degrees max. This might be maxing out the cooling, though, and maybe -5 degrees is enough. I guess you assess it by taking some darks and having a look at the noise at that temperature for given exposure times. Is there a way of actually measuring the noise level against a benchmark to know what's acceptable?
What increments? Thinking maybe 5 degrees increments? eg -10, -5, 0, 5 degrees etc. Or is that too excessive, and 10 degree increments is enough?
How often? I understand with time the darks will change. Read one guy uses a kind of "rolling library" where he takes a few new darks every few weeks, deletes the older ones, and makes a new master. Alternatively make a whole new library every so often. But how often? 1 month? 3 months? Yearly?
Any other thoughts or things to add?
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