Didn't read all the comments in detail, but you will also need a good, sturdy tripod and a remote shutter release if you're going to go longer than 30s exposure.
Sturdy tripod is self-explanitory. You don't have to spend $1500 (unless you want to), and you can always rent.
Remote shutter release is needed because I believe the maximum time for Canon is 30s exposures. If you want longer, you need to use Bulb mode, which means you need to hold down the shutter button. Not ideal, however most/all wired remote shutter will have a 'lock' which lets you keep it open without needing to hold the button down. Or if you get one of the fancier ones it'll allow for an appropriate time without you need to release the button after counting using your watch.
Last, use Mirror Lockup, and ideally the long exposure subtraction which will take a 2nd shot of the same length but without opening the shutter in order to subtract generated noise from the exposed image. Of course, it'll be 2x the length of time.
I have a manfrotto 055CXPro3 with an Acratech ultimate ballhead, never tried exposures that long but i think i should be fine?
That link about the long exposure noise reduction seems like a great read, thanks!
I'd say that's probably a pretty sturdy tripod, unless you overload it of course. You can also hang a small weight/bag so that it's putting most of the weight on the tripod in order to help dampen out any vibrations from wind. Don't know if there's a small hook on the bottom of the center column like there is on my Benro, but you can always rig up a something from the a piece of string/rope to something that has some decent weight.
If you don't want to go to that trouble, you'll almost certainly be find unless you have a strong and/or gusting wind conditions.