I had an old Oylmpus E410 series on a dobsonian 6".
A few pics in my portfolio - I'd have to a 10" or bigger would have been better.
I tried secondary focus (aiming camera at focal lens) but then bought an adaptor to go primary focus.
With no disrespect to anyone on ePz, take a look at the astronomy forums especially the photography sections for kit advice and possibility of stacking software.
I think I'd possibly have got better images with a refractor, however for what I spent was happy to achieve the images I took.
