Yep, what Jeanette just said.
This is exactly the method I did for this shot a few years ago: see attached - it works quite well, the idea of taking short exposures isn't that necessary IMO.
I used an Orion 80ED, small chip SXV-H9 CCD camera, 1.25" astronomik LRGB filters and 5min sub exposures all round.
By the way, that is a beautiful rendition of the sword Peter, once you bring out the core a bit better and be careful here it is very easy to make it look unnatural, you will have a fantastic shot for sure.
JJJ you're becoming a right astrophotographer
