Hello, I have an ST4000xcm and an ST8xme. The temperature in my observatory last night was 74 degrees. I got the ST8 down to 14 degrees below ambient but the ST4000 could only get to 5 degrees below ambient. Is this because of the difference in CCD sizes? Both camera fans are working. I'm not interested in water cooling. If it is the CCD size, I would expect the cooling to be more robust with a larger camera. Thanks, Bob
Hi Bob, I'm just another customer, but while you wait for other ideas, I was thinking it could be the large current draw with the cooler running nearly full-tilt. Are you powering them off the supplied AC adapter (that should handle it) or your own DC supply, or extended length wiring? For fun, you could also try cooling it in stages, and see what happens, eg see if you can get it to go to lower then even lower. You could also check the power supply voltage.
Below ambient? 5 degrees is very little. Do you mean below zero? If below zero, then it's simply the difference in sensor size. The larger chip puts more load on the cooler stack.
I did mean below zero Doug. In my USAF days, many temperatures were compared to relative ambient conditions. I'm surprised however, that SBIG didn't compensate for the CCD size. Thanks, Bob
I had already tried what you suggested Colin. But according to Doug, he believes the CCD size is the reason. Thanks, Bob
That would require a different camera platform design. Larger thermoelectric cooler, larger heat sink, bigger fans. In other words it would have been an STL camera instead of an ST.