I wanted to show the benefit that DSLR cold finger sensor cooling provides in image processing - specifically the ability to remove the influence of Dark Noise associated with the CMOS sensor. I have attached two recent files, actually from last night, both shot with the sensor holding at -10C. The first one is a 1/4000" bias offset frame shot at -10C, and second one a 194" dark shot at -10C; both shot in RAW but converted to jpg for resize for the forum. I have carefully examined the RAW files in Photoshop and cannot detect any significant difference. Click on them and examine them, you will be hard pressed to see much difference. Cooling works. Can you tell them apart? The left one is the bias offset frame and the right is the 194" dark. I can tell you that it doesn't matter if the dark sub is 330" the result is the same when the sensor temp is held at -10C.
Hi Glen, you are persistent aren't you ? Still working away at this project. Very commendable.
I can't see any difference either. No apparent noise on either. Nice work. I'll get back to this one day when I've finished sorting out the 8F8 scope project.
Having just got a cool box from Peter - I find I can do DSLR shots between 1200 to 1800 secs no problems now. I set the TEC to 3-4 degrees, which means the Camera chip reports around 8 degree to BackYardEOS.
I am pondering if I should go lower? The set point was to avoid dew, but if the camera is a constant heat source that's adding say +4 degree to the TEC - should I am for more aggressive cooling?
At 2400 seconds on a dark frame I can start banding of thermal current.
I am not surprised a cold finger produces such stellar results - well done!
If your camera is in a sealed box you can put a dessicant pack in to absorb any moisture, or fill the box with Argon. Just make sure the camera is dry internally as you don't want frost on the front anti-alysing filter. You can push Argon in through the front and cycle the shutter a few times.
