Thanks all, I aim to collect more data and combine it.
I could not get any color data with the 100ED last night but I dug up an image with some overlap from here
http://www.iceinspace.com.au/forum/s...ad.php?t=27634
Excised the common regions with RegiStar from the colour and narrow band images and combined in ImagesPlus.
Result of NB+COL 1.5MB
http://members.optusnet.com.au/~chee...mcnb+col_L.jpg
This was the aim all along use the 150mm diameter FL 640mm F4.25 achro for collecting dim nebula data in narrow band and the 100mm diameter FL 675mm F6.75 100ED APO for colour. They both have FR/FF fitted so their fields are very flat. Both have 2.7 inch Astro Physics focusers to minimise vignetting on a full frame camera . These focusers also easily carry the now 2.2kg fridge!
This method allows me to get really deep images from a light polluted site.
Below are colour, narrow band and finally combined.
Bert