I took 40, 30-second pics of comet 46/Wirtanen (guided on stars) recently (along with darks and bias frames) with my Canon EOS 7D and 4" refractor and have been trying to put together a shot of the comet. I followed Harry's tutorial using the Comet Alignment process in PixInsight. Got what I thought was pretty good shot of comet without stars and a decent pic of the stars (comet blurred). I used a star mask on the comet pic and then using pixelmath tried to add the stars image to the comet image - that's where things went south. In the new combined picture all the stars have a bright halo around them. I have tried various settings for the star mask but to no avail. Any suggestions would be greatly appreciated.
Thanks,
KnoxW
