For imaging on an NEQ6, a C14 would really be pushing it, so would a C11, you are better off sticking under 2000mm, and under f8. A RC10 would be the biggest I would put on a NEQ6 for imaging.
Also SCTs arnt the best choice for DSO astrophotography, unless you are doing planetary or visual, and RC or larger newtonian is a better idea.
