ngc1535
PixInsight Ambassador
With regard to hot pixels- for some sensors these warm/hot pixels can accumulate charge in a non-linear way. Matching darks taking at the same usually takes care of things... but typically darks (or master darks) taken from the recent past are used and they will not necessarily perfectly subtract hot pixels. Changes in temperature, exposure time, scaling (optimization)... all can leave hot pixels behind.
You are definitely correct you need to remove them before debayering.
(which is what I demonstrated in the video)
You are also correct that hot pixels and other problems can be rejected during image integration. However... you can't get there if you cannot align the images first. If the stars in the image are bright enough- hot pixels will not matter much. But this is the reason I made the video. For many OSC and CMOS imaging situations where the exposure times are very short- hot pixels become important to reckon with.
Your hotpixels will not shift due to dithering. Only the stars (signal) will. The *will* shift after you have registered your images- which is why rejection will take care of them at that point.
-adam
You are definitely correct you need to remove them before debayering.
(which is what I demonstrated in the video)
You are also correct that hot pixels and other problems can be rejected during image integration. However... you can't get there if you cannot align the images first. If the stars in the image are bright enough- hot pixels will not matter much. But this is the reason I made the video. For many OSC and CMOS imaging situations where the exposure times are very short- hot pixels become important to reckon with.
Your hotpixels will not shift due to dithering. Only the stars (signal) will. The *will* shift after you have registered your images- which is why rejection will take care of them at that point.
-adam