Subsequent to my original post:
http://forum.orpington-astronomy.org.uk/index.php?topic=6472.0
I've now spent some time reprocessing this image. Here is the result:
(http://gallery.orpington-astronomy.org.uk/albums/userpics/10053/normal_2010_11_18_M15_A.jpg)
Gone is the nasty artefact around the bright star, upper left of centre and, as Duncan suggested, more stars have risen above the merk. The image has also been flipped top for bottom and a larger crop applied.
Much better Phil - nice work
That's a huge improvement Phil. Well done.
Carole
Phil, that's much better. I didn't pick up on this before but I'm assuming this was with an IR cutoff filter i.e. r+g+b and not an IR pass filter?
When are you going to try longer sub exposures?
Robert
Thanks, everyone.
Robert, yes it was an IR cutoff filter. Once I get the mount fully sorted out I shall be attempting some long exposure subs.
Much better Phil. A very natural looking result.
Gone is that overprocessed look.
Mark
Thanks Mark. After a lot of head scratching I think I might be getting a handle on how to process this type of image.