location used for observing terrestrial or celestial events

An observatory is a place for making observations. The term is most used for astronomical observatories, which are places for looking at the sky. A modern astronomical observatory has a large telescope, or several. It is usually high up on mountains or hills, because higher places have cleaner, clearer, dryer air. Observatories also have to be away from places that have lots of light pollution, like cities. Too much light can make it so that the astronomers cannot see out of the telescope very well.

Griffith Observatory
in Los Angeles, California.