As some of you are aware I built a Peltier cooled fridge some time ago to cool my Canon 5DH. Below is a plot of ambient temperature and temperatures inside the fridge from a warm start. It is obvious that as the ambient temperature changes the fridge temperature will follow.
I have ordered a Peltier temperature controller from here
http://www.tetech.com/Temperature-Co.../TC-48-20.html
and it is arriving today. I will post up results later. The main aim is to get a constant temperature inside the fridge so all darks and lights are perfectly matched in the temperature they were taken no matter what the ambient temperature is doing. This is the main reason why ICNR works better than any other method. If the temperature of the camera does not vary by about 0.5C dark subtraction should now give better results than ICNR if the ambient temperature changes quickly over an imaging run.
Also all you folks with cooled Canon cameras and QHY8 cameras should be able to control their temperatures as well. They do have cheaper versions without the display and computer control.
My guess is that with care the temperature would not fluctuate by more than 0.5 degrees C. The controller is capable of holding the temperature at about + or - 0.1C variation. This of course would depend on the implementation.
Bert