[raymo]

Jacob, I wouldn't bother with flats at this stage, you won't see any
difference in the end result.
The background is quite a lot too light, which washes out the galaxy.
If you darken it, it will make the galaxy pop, and beneficially, will hide
some of the noise. More subs will help to reduce the noise also.
Your image is lacking colour; this galaxy should be distinctly blue.
An LP filter might help if you are badly affected where you are. You
will probably just have to attend to the colour cast it introduces.
I have attached an image showing how 83 should look using shortish
subs like yours,[but using JPEGS]. My background is actually a smidge too dark.
raymo