The 600D is excellent, and I really like using mine. A spare battery is a must, or the battery grip that takes 2 batteries.
U cajn get these as aftermarket on ebay for around $70 and they work fine.
Also a remote that can set up a series of timed exposures.
I spent $15 on eBay and it works perfectly well. It walks u thru set up of: Number of exposures>Exp Time>Time between Exp> etc. It plugs into the 2.5mm plug on the Canon and has a decent cord length.
This one:
http://www.ebay.com.au/itm/LCD-Timer...6690d1e&_uhb=1
U can drill and screw in a couple of hooks into the Dob base to hang the accessories on or glue Velcro to them.
U wont be disappointed with the 600D and I see the sell for about 400 body only. A big plus is that the LCD folds out away from the body and I have found this very useful since u can set it up so you don't have to bend and twist around to see it when u are focusing. It also has a 10x magnification which helps when focusing too.
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Trev