Experiment #1 North Circumpolar Motion of Stars

Experiment #1 North Circumpolar Motion of Stars Department of Physics, University of Colorado at Denver Physics 1052 (General Astronomy) Experiment #1 — North Circumpolar Motion of Stars The purpose of this experiment is to develop a better understanding of the daily motion of stars near the North Celestial Pole by observing the motion of a particular set of stars (the seven stars of the Big Dipper, part of the larger constellation Ursa Major) over the course of few hours. Polaris, also known as the North Star or Pole Star, is very close to the North Celestial Pole (within 1o), so it does not appear to move in the sky as the other stars do. It will serve as your reference point, much as it did for sailors and backpackers (before Global Positioning Systems were available). In this experiment, you will make three observations of northern sky, one every 90 minutes, so pick a night when you have plenty of time. You don’t need to stare at the stars between observations, but you will probably want to get started as soon as possible after sunset. For each observation, you will sketch the position of the Big Dipper relative to Polaris, the zenith, and the horizon. The sketches must be sufficiently accurate so that you can distinguish the difference between linear and circular motion over such a short observation time. If you have the time, wait two hours between the observations for greater effect. You must record time of each observation within 5 to 10 minutes of accuracy. Begin by finding a location with clear view of the northern horizon. If city lights obscure your view of the Dipper, you will need to find another suitable location. Face north and use your star—finder to locate Big Dipper. The two stars in the cup of the Big Dipper point towards the Polaris. Polaris is located in the tail of Ursa Minor (the little Dipper); it is the last star in the handle. Some stars in the Ursa Minors are hardly visible with naked eye. Don’t worry about them. We only need Polaris. Use Polaris as the fixed star on your sketch. Please see the figures on the next page before you make any sketch. Orientation of your figure should look something like the top figure, though larger than this. Note that the Zenith, not Polaris, is the point in the sky directly overhead. Polaris should be directly in front of you — a line drawn from the Polaris to the point of the horizon you are facing should be perpendicular to the horizon. If your view is more like the bottom drawing, you are looking too far to the east; rotate left until your view is like the top drawing. Sketch the position of the seven stars of the Big Dipper relative to Polaris and record the time. Wait 90 or 120 minutes and observe how the locations of these stars have changed relative to the Polaris and to the horizon. Record the new location on the same sketch, as well as the time. Repeat this procedure one more time for the same time interval as above. Make sure that the positions indicated on the sketch are clearly identified with the times you record. Your report should include one sketch with the location of the stars of the Big Dipper shown at three different times. It should also include your interpretation of the observed motion of these stars. Are they moving in a straight line or circling a particular point? Or, do they follow some other motion? Also describe how this motion relates to the motion of the earth; are the stars actually moving, or does their apparent motion result from the daily or seasonal motion of the Earth? Department of Physics, University of Colorado at Denver Physics 1052 (General Astronomy) Zenith Polaris West North East Horizon Correct orientation!! Zenith Polaris North East Horizon Incorrect orientation!! PLACE THIS ORDER OR A SIMILAR ORDER WITH US TODAY AND GET AN AMAZING DISCOUNT :)