Hi there, I was reading a novel recently where a character was using telescopes to watch vehicles moving on a planet at many light hours distant. The 'explanation' for his telescopes awesomeness is that it is designed to see distant stars and so seeing people moving on a planet in the same system is easy. However this does not seem right to me. My knowledge of telescopes and astronomy is limited but I'm interested to know what the limitations are on a telescopes resolution, i.e. is it the length, width etc. I'm also fairly sure I've read somewhere before that whilst the hubble telescope can see distant nebulae it would not be able to see the flag on the moon (which is what flagged up the passage in the aforementioned novel). Ideally I'd like to know how to answer questions such as "what dimensions would a satellite have to be in a 200km orbit to read size 10 font from my hand" Thanks!