In order to complete this project, you will need to locate North and East from a relatively open area. The easiest way to do this is to buy a cheap compass, but you can also orient yourself using a number of other means.

Fall Semester - Pegasus

Spring Semester - Orion

  1. On a clear night, go outside to an open area with relatively few lights around. Using a star chart, identify a bright star near the eastern horizon. With a sextant or astrolabe ( click here for instructions on how to build your own astrolabe), measure the altitude of the star (how far it is above the horizon) and also record the time. Record which star you used because you will repeat the measurement for this star a little later.
  2. Identify Polaris, the North Star. Measure the altitude of Polaris above the northern horizon.
  3. Once your eyes have become accustomed to the dark, find the constellation listed on the left (based on which semester it is). Print out the figure and compare it to what you see overhead. Can you see every star indicated on the figure? Circle the stars that you see (Note: in doing this part of the lab you may need to use a flashlight. If using a normal flashlight you may want to tape a piece of paper over the end in order to dim the light and preserve your night vision.) Take your time in making your observations to insure that you eyes are completely adapted to the dark. Also record the date and time of your observation and the sky conditions (clouds? fog?)
  4. Find the star that you used previously and measure its altitude again. Record the time of the observation.
    1. Determine how much time has elapsed since your first observation and divide this number by 1440 minutes (the number of minutes in a day). This is the fraction of the day separating your measurements.
    2. Determine how many degrees your star move through during that time. Because you are not observing at the equator, the star has not moved directly higher in the sky, but also slightly to the side (yet you only measured its change in altitude). To correct for this, divide the number of degrees above by the cosine of your latitude (the latitude of State College is 40.8o, the cosine of 40.8o equals .757)
    3. Divide this number by 360o (the number of degrees in a full circle). This is the fraction of a circle that your star moved through.

Worksheet to be handed in