Quote:
Originally Posted by gregbradley
6. Cooling power of the camera. Colder cameras would allow shorter exposures as the noise floor overall will be somewhat less allowing a signal to show its head above the overall noise.
As a practical observation the most common subexposure for an astro CCD is 10 minutes. Sometimes you see 5 but that really requires quite a low noise camera.
Greg.
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Hi Greg,
I'm a bit confused by this. doesn't noise increase with length of exposure whether its cooled or uncooled?
eg. a 5 min exposure with an unmodded dslr will show noise but the same with a cooled ccd will show almost none?
or are you referring to sensitivity? so you could get sufficient details with a cooled ccd and that would not have as much noise?
not sure why 5 mins would need a low noise camera and 10 mins won't?