Hi Peter,
Some really tight stars in there.
I looked at your old version of this image with less data here:
http://www.atscope.com.au/BRO/gallery140.html
I cropped a small section around the keyhole of both images.
I hope you don't mind?
The older version has more detail & is sharper.
Is this your processing or just the different size image in terms of MBytes?
See the attached pic: