Hi, I am having difficulty processing a set of narrowband data in that I'm finding it hard to remove hot pixels. First to say that I have quite a small number of subs with each filter - 6 x 10 mins - but realistically with the weather having been so bad getting a 3-hour session of clear sky is in itself something of a miracle!
I guess that some of my problems may be caused by the fact that I dither, but it's the cosmetic correction stage that seems not to find the hot pixels.
For each filter I'm using the following script generated from sirilic:
preprocess images -dark=../MASTER/master-darks.fit
seqfind_cosme pp_images 3 3
stack r_cc_pp_images rej 3 3 -nonorm -out=../Ha
and it then registers the channels with each other before post-processing.
From a blink test of each channel, in one case the hot pixels have been removed but in the other two they remain. I have adjusted the sigma values up/down but no change other than the channel that has the hot pixels removed sometimes changes. It also seems to change each run - maybe with a change in the reference frame? - the last run I did removed none of the hot pixels from any channel.
Please can you advise how best to process a limited number of dithered subs or whether dithering is not recommended at all.
Lastly, where the hot pixels are removed they are replaced by dark values - is it possible to have an option where they are replaced by the median of the surrounding pixels?