Hi Dunk,
I see you have taken the scientific approach, from trial and error I can confirm that 30 minute Ha subs on an uncooled dslr is far tooooooo long
https://www.flickr.com/photos/803366...posted-public/
I wouldn't want to see the SNR or NSR on this one! And that is one of the chillier subs!
25 degs!
Cheers
Rusty