Hello all since a long time now I get the below vertical white lines in all my images (dark & light frames), is it normal for Class 2 chip? My problem is that there is no satisfying correction in my light frames after processing
I see what you mean - and this is normal. Class 1 sensors can have typically no more than 2 column defects; Class 2 can have a few more. The hot pixel at 1292, 805 is giving you a bright column x=1279; this looks like it may subtract out. You may have to dither to get rid of this in your imaging process. I also see faint columns at column x=1479,1689,2805; these should subtract out. There may be a weak column at 697 and 1246, but it is really hard to tell, and it should easily subtract out. I'm surprised you say "no satisfying correction" - the only one I think would be an issue is 1279. How old is the camera? Serial number? All CCDs will develop column issues and more hot/warm/dead pixels over time; radiation damage will make this much worse.
Ok, thanks for the reply. The camera serial number is X13060238, and I think it is about five years old but with very little use...
It doesn't matter how much use it gets. It matters how many cosmic ray neutrons hit the sensor over time. If you are at sea level it will be less; if you are at high altitude it will be more. Typically cooling reduces the impact of hot pixels and columns. In most cases after cooling and dark subtraction you can't even see them. If you have a really bad column then fix bad pixels is a good idea (you can set it up to do that automatically during calibration), and dither is always recommended.
