Last night I took some images of C/2016 M1 with my 100mm refractor (f/5.5). I wonder if that was too ambitious? I can see the comet well in all subs but when I try to use the comet alignment process in PixInsight I can't select the comet. Pix Insight will choose stars around the comet but never the comet itself. Does anyone have any tips to make it work or is it just an issue of focal length?
I usually load the full set of subs into comet align. Open the first and last sub from within comet align, use your STF to make things visible. Then click on the comet in the first and last sub. This assumes subs were taken at roughly equal intervals. I usually open one or two of the intervening subs to see if the comet has been identified correctly.
It's hard to see what's going on in your image. PI always seems to find the comet when I use it. Perhaps it's an SNR issue.
60 seconds should show the comet nucleus clearly. Images below taken with a 120mm f/7.5 refractor last night. Can't see that things should be much different at 100mm and with a faster focal ratio.
Attached a crop of the comet taken about the same time yours was taken. PI finds the comet even with other bright stars nearby. I don't think it is a FL issue.
I'm not sure what is going on. The images were 60 sec exposures at high gain with a ASI1600mm. I took images with LRGB filters and the problem is with the lum filter which should have the highest SNR. Interestingly comet alignment works well on the R, G and B filter images. I will keep experimenting and see what happens...