Likewise, I think the galaxy looks really good - you must be happy with that! Love the star colours too.
Within PI, suggest using MLT to reduce background noise:
Somewhere between 4 and 7 levels, with a Linear Mask to protect the galaxy. Need to play with the settings.
Then darken the resulting background a tad .... maybe using a Range Selection mask with HT to adjust the black points.
Lovely target ... have not yet tried this one.
