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By the way the 183C is a QHY camera. QHY is the brand. CMOS is a the type of sensor. The other main manufacturer is ZWO (their main competitor although I see SBIG is offering a mainstream CMOS camera to compete.
All these CMOS cameras except a few of the latest suffer amp glow. It shows up a light streak on the side of the image.
Amp glow disappears with the correct dark exposure. A master dark is several dark exposures at the same temperature, the same gain and the same offset and same exposure duration as the light exposures.
So its usually easiest to use one or two different settings and a temperature that you can achieve all year round and at around 85% power. That probably is around -10C for the 183C.
Exposure lengths may be 60 seconds to 500 seconds and possible longer if you do narrowband - 10minutes.
So make a dark library of say 12 x 60 seconds -10C and at one gain and offset (I don't think you need to change the offset, keep it the same for all).
Create the master dark using a program that will do that.
Make another at the next most used exposure times the same way, say 2 minutes (120 seconds) then 5 minutes.
The 183 you just use darks not biases and also use flats. Flats are another procedure. They get rid of vignetting and uneven illumination as well as dust donut shadows in images.
Amp glow can sometimes be not very noticeable if the signal is strong in the light exposures and it is more noticeable in dimmer images with longer exposures. 30 second exposures may not show much amp glow at all.
Dealing with amp glow in CMOS cameras is just something you need to be able to do. Its not really any different to CCD cameras which also need dark exposures. But CCD's do not have amp glow. But then neither do several latest model CMOS cameras like the 533, 2600, 410, 2600 and 6200 cameras (ZWO ASI numberings).
Greg
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