I will throw in another suggestion, the Skywatcher MN190 Mak-Newt. Its 1000mm fl and f5,3 so good enough and fast enough for DSOs. It does not need a coma corrector as it has a great front corrector, so its flat field and there are no diffraction spikes as the secondary is mounted on the corrector. Fully baffled, images compare to larger APOs, and it produces true colour rendition. I have had one for years now and will not part with it. The stock focuser is just adequate for imaging with a DSLR but with your camera (and mine), the Moonlight upgrade is recommended (Ron makes a special adaptor kit for the MN190). Its more expensive than a GSO imaging newt of the same size, and heavier (due to the corrector) but well balanced.
Current price is around $1699 from Andrews.
You would need a NEQ6 as a minimum for imaging with it, but with your camera i would suggest a heavier payload mount, i use a CGX these days.
Just my 2 cents. Note i have APOs and Newts, but the MN190 is the easiest to use as you don't need to worrying about reducer correctors, flatteners, or coma correctors - just stick the camera in the focuser and your in business.
