back to lab 1
- White poster board, 5x5 inches
- String, 8 inches long
- Paper Clip
- Plastic Drinking Straw
- Small Weight (sinker, washer, etc)
- Clear Night Sky
1. Draw a line one-half inch from the top and left side of the poster board.
Place the center of the protractor on the point where the lines intersect and mark
off the angles from 0 to 90 degrees. Make small lines and number every 10 degrees:
10, 20, 30, etc. Make a smaller line halfway between these to represent every 5 degrees.
If you have a sharp pencil you may want to mark individual degrees.
2. Make a small hole where the center of the protractor was located in step 1
-where the two lines intersect- and thread one end of the string through this hole.
Tie the end to the paper clip to keep if from slipping back through. Adjust the length
of the string so that it is about one-half inch below the numbers of the degrees
on the scale. Tie the weight to the free end of the string.
3. Use the string as a guide to trim off the excess part of the card
4. Tape the straw to the top edge of the card. You will use the straw to sight
through. If you aim at the horizon the string should be a 0 degrees. If you aim at
something directly overhead, the string should be at 90 degrees.
Use of the Astrolabe
On a clear night sight through the straw until you find the star or planet you
wish to locate. Use your thumb and finger to lock the string in place against the
scale markings. Read the height of the planet off the scale and record in on your