Thank you for your quick reply and sorry for my late response.
I have uploaded three groups of files to my Google Drive. There are three images which include the horizon, three images with the horizon cropped off (to eliminate its influence), and three images where I tried to manually align the shots including rotating them (centred on the comet's head). In all three cases I couldn’t get the images to align. There seems to be distortion going on. Is it possibly related to the fact that I forgot to turn off image stabilization on my Canon M5 while shooting from a tripod? There would be about 15 seconds between each shot since they are from the first, middle and last of each sequence. I just upgraded the program before trying again with no luck.
Here is the link to the files:
Thank you for looking into this. I have high hopes for your product,