Hello, I am continuing to work out procedures in HighStack Pro (HSP) Mode for my AC4040. I have had success recently in finally determining the correct procedure for getting the correct flats intensity that eliminates any residual fixed pattern noise in my calibrated subs and produced several nice asttrphotos. This last week I used these procedures on a target and got terrible pattern noise. In chasing things down I took new darks and voila, the pattern noise was gone. Comparing the darks to ones taken one month earlier, I found that average ADU count was several hundred counts higher in the recently acquired darks. The difference was that the cooler was working much harder at our hot desert temps in Phoenix this week compared to June, with the heatsink temp at 43 deg C this week versus 29 deg C in June. Obviously, I can acquire darks as needed or could raise the cooler set point during the summer, but I was surprised to see such a difference. My HSP stack time is 30 seconds and the frames are acquired at 300 seconds. Cooler outputs are around 75-80% now, versus 50-60% a month earlier. Any guidance from others' experience? And PS, During the Fall, Winter, and Spring at the same 0 deg C cooler set point, I used one dark library for 6-9 months.
O deg C, same as earlier darks taken at lower temperatures. Note: I am upgraded to all the latest Firmware, etc.
Thanks for firmware info. Remind me, what's your altitude? and ambient temperature when this happened? This is why we have those liquid cooling ports on the camera. Likely you've hit the limit on the delta T of the camera We'lldiscuss incase I have anything concrete to suggest other than liquid..
I am at about 600m and the temperature in the observatory was around 32-4deg C when acquiring darks. Looking at several dark frames, the reported temperatures are all 0C +- 0.1. This is close to the 35C delta T so maybe I was fooled by the cooler power being less than 100%. Liquid cooling has been difficult here for me and I have a blockage in the ports that would need service (already had that done once). Hard to keep cooling liquid running without deposits forming even with water treatments. For my hot summer months I'll probably be better off raising the target cooler temp and accepting a little more noise to avoid the cooler working this hard and associated variability.
