Thanks for the comments. I have been up all night now for three nights in four. What makes it worth it when you see something you've never seen before.
I tend to stack my data 1.5 times the native pixel count of my sensor. This with dithering and lots of frames increases the resolution due to the under sampling. One thing this allows me to do is then bin x2 or 50% which increases signal to noise by a factor of four. The image is now 75% of native pixel count about right for mosaics and the stars are now perfectly round.
This image is a starless version derived from binned x2 data and upsized to native sensor size. 9MB
http://d1355990.i49.quadrahosting.co...O_nostars_.jpg
Bert