Hi Peter.
On my monitor i see a mottled background with splotches of blue and brown.
Also there is a lot of noise.
Do you image from a very light polluted area? If so you might be better of getting shorter exposures but a bucket load of them.
For 27X300 seconds it doesn't look too good

Also there is no color in the stars and almost nothing in the galaxy.
Maybe it is just the processing, i don't know, the data is there and a Sidonio might bring it out better

PS: i am not a authority on processing so i might have it all wrong