Peter, don't get me wrong here, I have just had another good look at your image, and I'm not having a shot at your image, I'm sure you are more experience than me, however the way it appears on my screen is very over exposed, visually, and heaps of noise.
Like I said earlier it may be my monitor, it is only new, and it is suggested that I run it at the set resolution of 1400 x 900 etc.
I have been caught out before with making my images way to dark, and because I'm probably not very experienced in the way I look at star images I see others that are very light and think it is noise that I am looking at, where in fact all that stuff has to be there.
So, all in all your image is probably supposed to look the way it dose, and I have to get some more time under my belt and do some experimenting, with the processing side of things.
Cheers Leon