planetarium, theatre devoted to popular education and entertainment in astronomy and related fields, especially space science, and traditionally constructed with a hemispheric domed ceiling that is used as a screen onto which images of stars, planets, and other celestial objects are projected.

Why is a planetarium important?

Planetariums are the world's astronomy classrooms and theaters of public science education that have served perhaps a billion people during the past century. ... By showing the fascinating discoveries in astronomy and space exploration, planetariums are a major tool in increasing science literacy.

What is the difference between an observatory and a planetarium?

A planetarium is a 'sky theater' where special projectors create a simulation of the night sky on a dome ceiling. An observatory is a place where telescopes are used to view the actual night sky, so the dome of an observatory does open, unlike the one in a planetarium.