Robin – I would agree with that but I don’t think that “science” is the main objective in these cases. Jager and Rhemann are very careful with what they do but there is always a concern that so many complex steps can lead to artefacts. I don’t think that this is the case here but I have seen plenty of examples online from less experienced imagers.
Personally, I think the whole idea of separating the comet from the background and then processing each one separately is a bit dodgy but I know that others will have a different opinion!