Quote:
Originally Posted by strongmanmike
Another concise analysis Richardo
To answer your question Cliveus, I use -30C year round so I can be lazy with the same set of darks but given Richards explanation I should probably exploit the low read noise of my ProLine better and go lower temps in the winter months 
Rich, I understand dark libraries should be re-shot periodically, how often does one need to redo dark libraries to keep exploiting low read noise and cooling?
Mike |
you really need to measure it to know how much difference the extra cooling will make. In that data I posted is some measured data from Tim Khan's ML8300 running at -25C with and without light flood (Page 17)
He has very low read noise so his cooling at -25C and no light flood is sufficient for a 400 second exposure
of course none of this matters with bright objects shot in bright skies with broadband filters. The background signal levels are way larger than the noise contribution from dark signal components.
as far as libraries go: I have seen that the ambient temperature can affect the bias level a tad. Since you should NOT use dark scaling when using the light flood, you might want to take darks at extremes of ambient temperatures encountered during a year of imaging. There's really no reason to toss them unless you are picking up more costmetic defects or you have a long term bias drift issue which I doubt.