Hi Eeda,
i'd probably suggest a 700d (or older) rather than a 750 or 760d simply because they have larger pixels.
however all entry level dslr's are all great you can't really go wrong unless they are not compatible with capture software. i'd check compatibility with astrophotography software such as backyard eos before deciding really ...
www.kogan.com.au has cheap - grey import prices. jbhifi has ok prices but note that some listed are grey imports also.
cheers