Thanks to some comments on a couple of other forums about the star registration being off and some odd bi-colour fringing on some of the stars, I decided to have a go at using Registar (I had relied on the align tool in Maxim before), I reprocessed the image and put it at the following link
http://www.pbase.com/imaging_the_hea...50637/original
The original version is the one before it for comparison, the colour fringing on the original image is more noticable in the corners and at full resolution. I will be using this program in future and might even do some reprocessing on previos images
Best wishes
Gordon