Sorry Greg, I agree it looks great at first, but when you dive into the high res the the stars look chunky.
The data is fantastically deep but because you've stretched the heck out of it it looks unnatural.
I encourage you to have another go - but tone map so you remove the stars first, Starnet++ is perfect for this - then stretch it as you have & the pop the stars back in.
Here is a great video tutorial by
JP Metsavainio on how it's done.
https://www.youtube.com/watch?v=EQlGsM-S8vM