Wei-Hao Wang:Tony Gondola:
I go back and forth with this all the time, remove stars or not. Overall, I really would rather not remove them as no star removal process is 100%, disappearing stars or tiny galaxies is all to common. Not to say I don't still do it but the general star reduction tools out there are so good that I do so less frequently.
I think the key is why to remove stars? To just stretch the nebula? As I mentioned above, this is not my cup of tea. On the other hand, some other processes are just better done on a starless images. Noise reduction is one of them. While tools like NXT can do some smart star-background separation and only smooth the background, but when the strength is set to above certain point, it makes the stars soft. So when aggressive NR is needed, it's much better to do it on a starless image first and then add the stars back. Even if some stars or tiny galaxies are mistakenly preserved or removed, this doesn't harm the NR process and the image won't look unnatural once the stars are added back, especially with careful masking during the NR. Same goes for sharpening. Many sharpening algorithms can either over-amplify the stars, or leave artifacts around stars. So for sharpening nebulas and galaxy details, it's much better done on a starless image. Again, here even if the star removal process mistakenly removes some tiny galaxies, those galaxies get added back later. Although such small numbers of galaxies would have escaped the sharpening during starless stage, they will look just fine in the final image.
In short, I fully agree that no star removal is 100% complete (without false positive and false negative). However many processes that can be better done on a starless image does not require 100% star removal. What's mistakenly removed will be added back later anyway.
Agreed, when I do, do it, it's to improve both the stars and the non-starless parts of the image.
