The colour balance is not quite right but all the detail in both objects are there without blowing out any bright areas. If you look carefully there are quite a few dim galaxies peppered in the background.
I still have a lot of learning to do with this method as it produces as many problems as it solves. It is an unwritten law of the Universe that you don't get anything for nothing.
Thought it was worth this large image 2.7MB
http://members.optusnet.com.au/~chee.../OC&CA_HDR.jpg
Details
Canon 5DH, Canon 300mm F2.8L at f/2.8, 20x1 min, 8x4 min, 4x16 min, at an ISO of 500, ambient temperature 8 deg C at start 6 deg C at finish. Fridge temperature -11 deg C. No sign of condensation yet.
Used Images Plus and RegiStar to produce three stacked images at each exposure level and used EasyHDR to produce an LDR TIFF.
Bert