I spent a good deal of the weekend reprocessing this to deal with the star alignment issue first pointed out by strongmanmike (which is now fixed) as well as some small colour improvements suggested by Greg (Bradley). I think it is now as good as I can get it. The star alignment issue appears to have been a hiccup when I originally ran Registar, but as I mentioned in the original thread I found a minor "dark pixel" problem when using bicubic interpolation in Registar. I searched the internet for an explanation of this - see
http://pixinsight.com/forum/index.php?topic=1992.0 for Juan Conejero's (Pixinsight) description of the bicubic problem. It seems that Marc's (multiweb) suggestion that it was caused by the "sharpness" of the stars was not far from the truth. I would be interested to hear from other Registar users' experiences here.
Anyway, here's the reprocessed image:
http://upload.pbase.com/image/149199545