[tornado33]

Was looking at some past images Ive done, and decided to check darks I did in summer and compare to ones I did 2 nights back when it was very chilly.
Both are full res crops from same part of image.
One was at an ambient temp or around 20 degrees, the other at 8 degrees. Look at the difference in noise. Bert has the right idia, making a fridge to go round the camera. DSLR's dont need to be cooled to 30 below. If this dark is so dark at 8 degrees, at around zero thermal noise would be almost non existant.
Scott