Originally posted by jbinpg You don't need a Peltier when you shoot at ambient temperatures of -20C up here in the north country in the winter !!!
Yes, low ambient temperatures definitely help but even at -20C ambient the sensor would be at 10-20C since the sensor heats up to around 35C above ambient, its not that much different from a CPU in this regard.
Every temperature rise of 7° the image noise doubles, and like anemone said, long exposures are like video or even worse.
Note these numbers apply to Canon CMOS sensors but i dont think Pentax/sony sensors behave much different.
When shooting starfields all this is not that much of an issue, but when you try to get the faintest signals from the red channel you want to have the noise in there as low as possible.
Edit: dedicated APSC+ astrophotography cameras (Apogee, FLI, SBIG,...) are 4000-40000$ without filter wheel. One day...
Last edited by Bewatek; 01-18-2016 at 10:57 AM.