How to Make an Astrolabe

The astrolabe is a classical scientific instrument, fundamental in its importance to astronomers and mariners alike. But although the astrolabe was refined over time by explorer after explorer, some of its basic principles are quite easy to grasp. To that end, creating your own astrolabe can be quick and easy, and it's a welcome tool for the budding astronomer.

Things You'll Need

• Half-circle protractor
• String (12 inches)
• Weight (nut, bolt or washer, for example)
• Straw
• Tape

Instructions

1. Locate the hole in the middle of the straight edge of your protractor. If your protractor does not have such a hole, drill one into place.

2. Tie one end of a foot-long piece of string to the hole.

3. Tie a weight--a nut or a bolt will do just fine--to the other end of the string, so that the string hangs straight down to the ground, exactly crossing your protractor's 90-degree mark.

4. Tape a small straw to the long, straight edge of your protractor. This straw will serve as a sight.

5. Sight your stars, with the curved edge of the protractor facing down. By noting which degree mark your string happens to cross, you should be able to determine how many degrees a star is above the horizon.

Resources

• Read this Article in Spanish