If you look up into the sky on a clear night, you will see thousands of stars, but how do you know which star is which? Luckily, the stars form groups known as constellations, which can help you find your way around the heavens.

Early astronomers noticed that the stars formed groups and that these groups moved in a regular way across the heavens. They began to use characters, animals, and objects from their myths and legends to remember these groups. Most of the constellation names we use today date from Greek and Roman times, but some go back even further to the Egyptians, Babylonians, and Sumerians.

Finding the North Star
The North Star sits almost directly above the North Pole, which makes it an excellent way to find due north. It is visible all year in the northern hemisphere at the tip of a constellation called Ursa Minor (the Little Bear). To find it, you can use another constellation called Ursa Major (the Great Bear). Seven of its stars form a shape that is known as the Big Dipper. The two stars that form the front of this shape point to the North Star, which is the next bright star you see.

A group of 12 constellations can be seen in both hemispheres. The ancients called them the zodiac, from the Greek word for animals. Most of them are named after animals, but some are human and one is an object. The zodiac runs along a path in the sky called the ecliptic, which is at an angle of 23 degrees to the equator. The Sun, Moon, and planets also move on paths close to the ecliptic.