SKYWATCH PROJECT:

THE CONSTELLATIONS AND MOVEMENT OF THE STARS

TIME REQUIRED: One entire, clear night.

EQUIPMENT REQUIRED: Sleeping bag or a warm blanket, warm clothing, food and liquid refreshments of your choice, a star chart (if the one we passed out is too simple for you, your T.A. can give you a more complete one, for instance the monthly one in "Sky and Telescope" magazine), and a homemade quadrant to measure elevation (see the Celestial Navigation skywatch writeup for a drawing of a simple quadrant.).

BACKGROUND: Many Astronomy students wish to learn the constellations. Here is your opportunity both to learn about them and gain Skywatch credit. You will also see how stars move through the sky on paths that may surprise you.

WHAT TO DO: On a clear, dark night, preferably away from city lights (if the weather cooperates, pick a night without a full moon), begin by finding the north star, Polaris. Look in the northern half of the sky about 45 degrees above the horizon. Polaris is located at the end of the handle of the Little Dipper. Use your home-made quadrant to measure its altitude angle above the horizon. Now use your star chart to pick out at least four constellations and memorize what they look like. Pick one prominent star in each constellation and measure its altitude above the horizon. You may need a friend's assistance to do both sighting and reading simultaneously. Repeat this process every hour or so, recording the time and altitudes of the stars. Also make a sketch of the orientation of other prominent stars in each constellation relative to the ones you have measured.

Between measurements, try learning a few more constellations. The final step (the next day, after sleeping!) is to prepare a graph showing the elevations at each hour through the night. (Your T.A. can help if you are not familiar with making graphs). Why do some stars change elevation more than others? How do they move relative to Polaris? Do all stars move from east to west? Do the orientations of the constellations change through the night? Does the apparent brightness of a given star change through the night? Does its amount of "twinkling" change?