I have been busy trying out both Photomatix aand EasyHDR. This is one result that I thought was worth putting up. I have been playing with all the variables to get a feel of what is happening.
Details
Canon 5DH, Canon 300mm F2.8L, Hutech LPR filter.
Exposure details 60, 120, 240, 480 seconds, at an ISO of 200.
Large image 2.4MB
http://members.optusnet.com.au/~avandonk2/Ehdr_car1.jpg
Used EasyHDR to process these four images from 16 bit tiffs from Raw. Only used PhotoShop to adjust levels and curves and saturation.
Next thing to try is to take many sets of exposures and moving the orientation of the mount betwween sets so we can median stack many of these in RegiStar to enhance signal to noise of the faint nebula. The stars will also turn out rounder.
It is important to have the mount perfectly polar aligned so the alignment in these programs works properly.
For comparison here is an image with the same optic etc but done the usual way (stacking lots of the same exposures) and the stars all get overexposed and washed out for colour to show up the nebula.
Large image 2MB
http://members.optusnet.com.au/~avandonk1/CARsmal.jpg
Bert