Thanks for the comments folks. Looks like the weather and Moon will halt data collection for a while. So I squeezed out what I could from the data I had.
The mosaic is made up of two panels. Taken with the Canon 5DH and Canon 300mm F2.8L at f/5 and 400 ISO. The fridge temperature was at -5C so the sensor temperature was 12C.
LHS
Exposures 10x1m, 5x4m, 17x8m, 19x16m.
RHS
Exposures 10x4m, 10x8m, 10x16m.
The 1m exposures were needed in the LHS panel to record Antares without saturating too much.
I used my HDR process to produce the two panels and then used Registar to produce the mosaic. A lot of fiddling needed to hide the join.
More data is needed but here is a 8MB image
http://d1355990.i49.quadrahosting.co.../rhomosbig.jpg
The reflection nebulae and dust in this region are very faint so maximising the signal to noise ratio as usual is the one factor that gives any sort of decent image. Stacking many dithered images does really minimise any residual noise. Just compare the LHS to the RHS.
Bert