Star Charts and Planispheres

A star chart is like a map of the sky. It shows where the stars and constellations are. A planisphere is a special round star chart that you can spin. You turn it to match the date and time, and it shows you exactly which stars are above you right now.

How Star Charts Work

Star charts show dots for stars and lines connecting them into constellations. The brightest stars have bigger dots. You hold the chart above your head and match it to the direction you are facing. Star charts are made for different parts of the world because people in different places see different stars.

Using a Planisphere

A planisphere has two round pieces that spin on top of each other. You line up the date with the time on the edge. A window shows you which stars are visible right now. Planispheres are great for beginners because they are easy to use outside in the dark.

Fun Facts

• The oldest known star chart was made over 3,000 years ago in ancient Egypt.
• A planisphere only works for the part of Earth it was made for, like the Northern or Southern Hemisphere.
• Modern star charts can show more than 5,000 stars visible to the human eye.

Did You Know?

Before GPS and compasses, sailors used star charts to cross the oceans and find their way to distant lands.