noise or no noise, a DSLR isn't a deep sky camera and as such suffers from thermal noise as you well know. The other thing is the 500 series is only one step up from the 1000 series of canon plainly put they are virtually the bottom of canons range the 5 series is phenomenally better in regards to noise as its the top of the range camera. though if you where purchasing a 5d to do the job of a cooled astro ccd? it wont come close. that is my thoughts on the situation.
brendan
