I agree with Gary - really you have to be a mac-sochist
to buy/use a mac exclusively for astrophotography (unless its for film astro work only - in which case it is better to use a mac) I am in awe of the clever hardy true believers that do so, but life is too short, and it goes against the mac credo 'it just works' and the point of using macs to slave away at the frontier/coal face with noob/user unfriendly software IMO.
there are recent developments, and continue to be so, but everytime there is, the usually free/cheap and choice plentiful pc stuff jumps even further ahead, so defeating any catch-up advances on macs.
But I'm with Gary, mac's rule!
just not in astrophotography
btw the bundled software with camera will allow you to do what you want, never tried it tho.