Celestial navigation

Celestial navigation is a method of navigation where a person figures out their location and direction using the stars in the night sky. It has been used by sailors to help them find their way in the night. They look for familiar stars or constellations, which will help them find their way. 
Celestial navigation involves comparing the angle of certain stars to other stars and how high they are above the Earth's horizon. By doing this, a person can find their longitude.