I currently own the Cano 1dmk2n and its really good but I'm starting to notice it's limits when it gets darker and the images get noisier, I have found cheap 60d around (or a 70d for the same price but not turning on) and was wondering if this would be a good add on to my collection to do some low light photos including astro-land spare photography and just anything else at night, please note I am trying to stick to Canon since I am on a budget and don't want to be buying two sets of lenses
I love the 1DII/n. Owned several of them, and will likely never get rid of the one last copy remaining. I love the fast performance, dead-on focus accuracy, and image quality. But it is not, as you well know, a "low light" camera.
Unfortunately, I believe that virtually any APS-C camera is going to disappoint for low noise. I shot the 60D up to 3200, but no further. The 70D could be pushed to 6400, but I didn't like it.
I would recommend a 6D. It contrasts very nicely with the 1DIIn as a camera built less for speed and more for just fabulous image quality. It is aging very gracefully, having found a solid niche in the photography world among both enthusiasts and professionals. And, of course, it's great in low light. I'd routinely push it to 6400 and 12,800 with no problem.