Thanks all. Kulnura is heaps darker then here
Eric, I used ISO 200 as ISO 800 will only allow 2 or 3 minute exposures before fogging out, and Im comfortable doing 10 minute shots so use ISO 200. I wont ever use ISO 100 though as I read that it compresses the dynamic range, whereas ISO 200 pretty much reads the data straight off the sensor. If I had skies like Kulnura or darker Id definately try ISO 800.
Shooting ISO 200 also sees that the bright cores of the galaxies wont over expose.
Scott