I'm trying my hand now at ISO 400 imaging (I usually use ISO 800). To preserve image fidelity I've done a few things differently:
1. Each day I shot at the same duration and create match dark to maintain temperatures
2. I try and frame the shot very carefully from the day I shot's starting position
3. I try and avoid longer duration shots when the moon is about
So the following is the fruit of my labour. With flats, flat darks and bias shots remove - this image is 30 shots totally 9 hours 25 minute of data on a C9.25 into a Canon 400D. The stacking is done in DSS and CS4 was used for levels and curves (and a very slight Gaussian blur on the dim region). I have combined 4 shots at 600 secs, 11 shots at 900 secs,
9 shots at 1200 secs and 6 shots at 1800 seconds).
I think my quality of shots is slowly creeping up!
Matt
PS
Thanks to Humayun for the image capture and processing suggestions! I've got a long way to go - but step by step I'm moving forward.