Hi Malcolm,
A most impressive image with great clarity and detail. Well done.
I'm very new to Astrophotography so I apologise in advance if my question is a dumb newbie one.
When I look at your image on my calibrated monitor it's as sharp as a tack but all the stars, other than the core, appear to have CA. I don't really know what colours the night sky has or how subjective PP is so I look at NASA pics to try to get a ballpark idea.
Is the CA normal (?) or is your post a work in progress?