Starting Up the Learning Curve

[Oscar in Bin (John)]

This is astrophoto number 4 for me so still at the bottom of a very steep learning curve. NGC253 taken Friday night with roughly 40% moon. Imaging with 130mm refractor and 1.6 extender. Nikon DSLR D700 unmodified, 18x5 min images with darks and flats stacked using ImagesPlus. I am pretty sure I got the ISO too low shooting at ISO400. The 5min exposure proved to be as long as I could go without starting to get too much noise.
Upside was this was the first time I managed to get camera control and guiding working.
How do I smooth out the edges of the galaxy where it is rather granular. Will more signal fix this?
Other suggestions very welcome.

[naskies (Dave)]

Nice work, John. I may be mistaken, but it appears that your focus was a bit off? I find that Bahtinov masks are an amazingly helpful focusing aid.

[midnight (Darrin)]

I'm thinking the same thing too that you're focus may be a tad off John.

Get this nailed down and it looks like there is some nice detail to be grabbed.

Darrin...

[Saturn%5 (Graeme)]

Nice work John.

[scagman (John)]

Well done John,

That looks really good.

I'm just starting down the AP road myself with a 127mm refractor so its nice to see something similar. Hopefully my 4th image will look as good.

Congrates.