Hey Josh, I guess I'm kind of 'old school' about astronomy, I specifically went out looking for a mount that wasn't 'goto'. With a small amount of patience and checking the IIS classifieds daily I picked up an 8" F/5 newtonian and an EQ6 (non-goto, non-synscan, non-everything
) as well as a few eyepieces, camera adapters and software advice for well under a grand. I've recently been looking at upgrading some of my kit, but I can't find a scope worth upgrading to for less than $2000.
I got into astrophotography because I loved looking at DSOs through the eyepiece but I new there was so much detail and colour that I was missing out on, so I'm quite happy to sit outside with my scope while the 'fuzzy photons' from my eyepiece resolve into spectacularly crisp images on my laptop.
Your 6" won't be terrible for astrophotography so my advice would be to upgrade your mount to a HEQ5 or EQ6 (best you can afford) and stick with your current optics until you can afford a bigger tube (or build your own
)
An interesting statistic is that a 12" scope has twice the surface area of a 10", so don't be fooled by thinking that you need to double your aperture to see any gains.
But having said all that, you could probably get a larger aperture Dob for the price of Newt + EQ mount, so it all depends on whether you're happy to stick with Visual observing until your budget can extend to all the gear you'll need for astrophotography. The thing I love about this hobby is you can spend as much or as little as you like (usually more than you'd like though
)