On top of the astronomer's house(d)

You are standing on top of a strange stone building, shingled with grey slate tiles. The slate beneath your feet appears to be sturdy, and could hold the weight of several men. At one end of the roof, a chimney rises up to the sky. At the other end, a strange brass telescope has been mounted, its metal slightly dulled with age.
The only obvious exit is down.
A battered telescope is pointing southward toward the sky