Could we, in theory, see astronauts waving to us from mars via telescope or alien cities light years away?
Sure, except for the distortions of atmosphere on both ends. The limits of magnification are at the end - looking at things smaller than the wave length of light.
i think its possible ,like if you had this big satellite tellescope that bounced off other satellite telloscopes you probably could see it just using your phone..
i am actually way fare away on a planet named Zagnuts and I am looking at you write now your such a cute Kitty ....hi ..can you see me know ..how about now ok now