My QHY247C camera shows amp glow and very high read noise at cold environment.
The attached file (QHY247C_Dark.jpg) is a 300s dark image taken at -15 degree Celsius (gain=0, offset=50). As shown in the image two distinct amp glows exist at the upper edge of the image sensor.
Also, very high noise is observed at cold environment. The attached file (Leo_Triplet.jpg) is a single 300s-exposure image taken at outside temperature of -15 degree Celsius (the camera was cooled to -20 degree and gain=3200, offset=150). The image take at less cold environment does not have this problem. The attached file named "M106.jpg" is a single 300s-exposure image taken at -5 degree Celsius of outside temperature (the camera was cooled to -15 degree and gain=2200, offset=100).