Have a look at our Objects in the Sky page. Have a look at A Guide Book to Astronomy to see if this career would suit you. Then check out some questions which other people have asked about astronomy as a career. There is also a tongue in cheek survey which may show if you have what it takes to be an astronomer and here is one astronomer's wry view . Dr Paul Murdin has prepared some information on Astronomy in the UK .
Astronomy magazine has some very good advice for first time telescope buyers.
You could also consider buying binoculars . The Space Scientist has answers to a lot of commonly asked questions and to some less common ones. Yes, it has been hit many times during the past billions of years and will be hit again in the future. You had better check out the collision rate and actuarial risk .