Wow -
That's a *huge* improvement!
It sure shows what great dedicated software like PI can do. I'm glad you got rid of most of the color cast from your last effort. It can take people years to figure out that their monitor's black level is incorrect...
It looks to me like you need more data if you'd like to stretch things further without bumping up noise too much. I think you're hitting the limit of what's possible with your current set.
You may want to apply so progressive chromatic noise reduction (or even simply selective desaturation) in the darker regions to get rid of the color blotches there. Maybe some selective sharpening in the more defined regions.
It seems the focus is a little bit soft, but that may be due to atmospheric conditions at the time. However, what you could do is use an alternate method of RAW->color conversion which does not interpolate pixels during the debayering process, but instead yields an image at 25% the resolution that only contains the *real* raw pixels. This method is also known as 'super-pixel color reconstruction'. I'm not sure if PI offers this but DSS should.
If your focus is soft (for whatever reason), the reduction in resolution will not cause you to lose detail, since it was never there in the first place.
However, by using the real raw pixels without interpolation, it is easier to keep noise under control as the traditional debayering process magnifies noise and can turn fine noise into coarse grains and blotches. You should now have an image that is less noisy and easier to perform noise reduction on. This method is quite effective for obtaining workable images from just a few subs.
All-in-all an amazing progression. Keep us updated!
