thanks for your replies guys. Zut, yes, i think this is much dimmer than the horsehead as my unprocessed subs i can just make it out. If I was under darker skies then yes i can go much longer. I have done various tests with different iso's etc, longest i can go is 7-8 mins at only iso 400. tried iso800 and longer subs and it wil go overexposed thus loosing heaps of data and around this time of the year, temp at night sits at 19 degrees outside at 12am according to my thermometer
, longer will definitely give me heaps of blue/red pixels.