Make an Astrolabe

Learn how to measure the position of stars when you make an astrolabe. You'll be using a tool that astronomers and seafarers used for centuries when you do this science project for kids: the incredible universe.

Make an astrolabe to track stars.
©2007 Publications International, Ltd.
Make an astrolabe to track stars.

When scientists describe the position of a star in the sky, they measure its position relative to the horizon. An astrolabe measures how high above the horizon the star is in degrees.

What You'll Need:

  • String
  • Plastic protractor
  • Weight (washer, rock, or fishing weight)
  • Pen and paper

Step 1: Tie a 12-inch piece of string to the hole in the middle of the crossbar on the protractor. Tie a weight to the other end.

Step 2: Hold the protractor so that the curved part is down and the zero degree mark is closest to you.

Step 3: Sit on the ground, and look along the flat edge of the protractor with your eye at the zero mark. Point the flat edge at the star whose position you want to measure.

Step 4: Once you have the star at the end of your sight, hold the string against the side of the protractor.

Step 5: Note which degree mark the string crosses. Write this down in your notebook. This number tells you how many degrees above the horizon your star is.

Step 6: Take readings for several stars.

Step 7: Return every 30 minutes, and take new readings. Notice the pattern in which the stars seem to move across the sky as the earth turns.

Have you ever seen a shooting star? Go to the next page of science projects for kids: the incredible universe to find out how you can.

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