And remember you'll need a parallel guidescope setup, or reasonably expensive and challenging to configure off axis guider (and either way a 2nd guiding camera). Imaging above 1000mm focal length and F/7 focal ratio is also not a lot of fun when you're a beginner, and that's the region you're in with the SCT unfortunately. An experienced operator MIGHT be able to coax an EQ5 and SCT to give exposures of a few minutes or so, but you have to be prepared to throw a lot of frames away. Do you have the temperament to cope with that?
Another thing to consider for next couple of years is La Nina - be realistic in how much dark sky time you can access (important for DSO imaging) and how many dollars worth of gear will be lying around between sessions. If you can work from your backyard from time to time that's a big bonus, especially for learning your gear.
Trouble is, you've shot M42 through your own scope, so let's face it, you're dead meat now.
