Ye PS curves really worked well in Allans Eta Carina image for sure.
I agree with Greg, 2 hours is a good imaging time, though I guess for very fast systems shorter will do. As for length of subs, for me, I try to get the histogram about 1/3 the way across from the left, showing the sky background has well and truly been reached. For me in Newcastle an image throuhg my 10 inch f5.6 scope and modded 350D using just the IDAS uv/ir filter, I cannot go more then 5 to 10 mins @iso400. With the UHCS filter I can go 1/2 hour subs, but in my uncooled camera I performed a test which showed I get less noise taking 3x10 mins rather then a single 30 minute sub.
I believe most dedicated CCD camera users dont normally do more then 10 minute subs anyway? I believe SBIGs can do up to 1 hour subs?
What Id do if I was the owner of SBIG was approach Canon to see about buying a run of their SMOS sensors but without the bayer filter array, ( in otherwords a mono chip) and tee that up to a 16 bit ADC. I could then sell a 10 megalixel dedicated astro camera for less then half the price of an STL11 with similar overall performance but considerably less dark current and absolutely positively no blooming.
Nice M45 shot Greg too, and thanks for the tip re the guide cameras. The QHY6 looks like a great buy, $300
here
Scott