Dear Andrew,
much better colors in your second attempt, you eliminated the green tint very nicely. But someting went wrong with the stars: the bright star in the upper left corner shows artifacts in the core and in general I have the impression, that you reduced the star size just a little bit too much. To sum it up: try to combine the colors of your second attempt and the star shapes of your first attempt.
In PI I simply would extract Lum form your first attempt, blur the second picture a little and make an LRBG combination by using Lum from the first picture.
Just my 2c, it is a nice picature as it is now.
Best Regards
Fritz