Dave,
This is very good effort. Not over-cooked. Pristine round stars , colours natural, noise well suppressed.
I like it.
You might want to try more focal length, and go a bit deeper, but it's all heading in the right direction as far as I can tell.
P.S.
Though I don't use my *ist D often, I still like the way CCD based DSLR's render colours
