Mars Team Online
Star Census
Activity Sheet
Try this experiment to measure the number of stars you can see.
1. Make an "Observing Device" from a bathroom tissue or paper
towel tube. Measure the diameter of your tube. Cut its length to be three
times its diameter. Through the tube, you will see only a small portion
of the sky. It would take 144 tubes to cover the whole sky.
2. One by one, face in each of the 4 compass directions (North, South,
East and West).
3. Hold the tube 3/4 of the way up from the horizon in each direction
and count the number of stars seen through the tube. Hold the tube half-way
up from the horizon and repeat the count. Repeat the procedure again with
the tube pointed a third of the way up. Repeat observations for the other
directions. Record your data below.
| Area |
3/4 up |
1/2 up |
1/3 up |
Total |
| North |
...... |
...... |
...... |
...... |
| South |
...... |
...... |
...... |
...... |
| East |
...... |
...... |
...... |
...... |
| West |
...... |
...... |
...... |
...... |
| Total |
...... |
...... |
...... |
...... |
| Grand Total |
|
|
|
.......... |
4. Add up the number of stars for all 12 sightings. If it takes 144
tubes to cover the sky, then you have observed 1/12th of the sky. Multiply
your sub-total by 12 to estimate the total number of stars in the sky.
Estimated total number of stars:_________ (includes the stars above and
below the horizon)
5. Add up and compare the three measurements in each direction. Why
do you see more stars in certain directions?
|