The challenge - improving digicam deep sky images.

These Dark Frames show the noise introduced into the digicam image by higher temperatures.
I shot this series of images with my Nikon CP995 to demonstrate the noise that is introduced with increased temperatures. We know that the CP995 takes very decent deep sky images during cold winter nights. The challenge is to produce these same images during high summer temperatures. One method is to shut off the digicam between pics. This greatly improves the images as can be seen in the series above. The very first image at an ambient temperature of 66 degrees F is the most noise free. The 10th consecutive image is the noisiest. Turning the digicam off for 10 minutes produced an image almost as clean as the very first one in the series. All this pales beside the last image shown above which was the 20th image taken after turning the digicam off for only 2 minutes during ambient temperatures of 32 F.
 

This set of Dark Frames was taken at 40 F ambient temperature (same settings as the 1st set).
In comparing these two sets it's interesting to note that the 10th image at 40 F ambient temperature has less noise than the 2nd image at 66 F. The 20th image at 32 F taken after shutting down the camera for 2 minutes has significantly less noise than the 14th image at 40 F taken after shutting down the camera for 2 minutes. 32 F or below is obviously a good temperature to take 60 second exposures.
 

I'm currently focusing on peltier cooling my digicam.
I was unable to sufficiently cool my digicam using a 12 volt DC Cooler for $34.84 from Walmart, a small aquarium air pump and air line tubing. Resistance and heat transfer in the tubing elevated the exit temperature from the cooler too quickly to make it feasible. Perhaps larger diameter tubing might work (I used 1/4" interior diameter) but it would be cumbersome to use. I've been able to achieve 30 F below ambient temperatures by attaching a peltier device to a plastic mockup of my digicam. But I'm not going to disassemble my digicam until I can achieve at least a 50 F differential. This probably requires water cooling my peltier, which I'm looking into. If I succeed I'll post the results as well as instructions and materials used here.