Managed to collect more data to increase the signal to noise ratio.
Large image 2.7MB, FOV 16x24 degrees.
http://members.optusnet.com.au/~cheekyfish/OR_85mm.jpg
Details
Canon 5DH. Canon 85mm F1.8, Hutech LPS filter, all at ISO500.
Current data
At f/2.8, 5X2min, 10x4min, 12x8min
At f/4 , 5x( 8s, 15s, 30s, 1min, 2min)
Converted from RAW to TIFF and corrected for flats with ImagesPlus. Stacked and aligned wiith Registar. Used EasyHDR to produce a LDR image from these eight images. The dynamic range is potentially 20 bits.
I also rotated the image to thhe orientation we are all used to. I am sure it has improved.
Bert