<p> ASTR 111 Semester Observing Project</p><p>Spring 2007</p><p>Spring 2007 Observing Project</p><p>Name: ______Section: ______</p><p>Due Date: May 1 (0101) or May 2 (0201), during lab</p><p>Instructions</p><p>There are 4 parts to this observing project: Celestial motion, motion and phases of the Moon, motion of the planets, and independent observations.</p><p>Complete the observations as instructed and record them in this Observing Log. You should also answer the questions at the end of each part. A cloudy night does not count as an observation. These are the observations you will be making:</p><p>Celestial Motion – 4 observations of the same bright star, each about 2 weeks apart</p><p>Motion and Phases of the Moon – 10 observations, taken over the course of two months</p><p>Apparent Motion of the Planets – 4 observations each of Venus and Saturn, each about 2 weeks apart </p><p>Independent Observations</p><p>You should make at least 15 observations of constellations, stellar systems, nebulae, galaxies, or other objects. You might have to use binoculars or a telescope. Record all pertinent information in your Observing Log. These additional observations can be made at any time, but should be spread out such that no more than 3 observations are made on the same night at the same time. You will receive extra credit for observations of Mercury, Mars, Jupiter, Uranus, Neptune, or a comet.</p><p>Total number of observations = 37 (minimum)</p><p>If you have any travel plans during the semester, an interesting comparison would be to observe the sky from different geographic latitudes.</p><p>Get in the habit of looking up when you go outside and take note of what you see!</p><p>Spring 2007 Phases of the Moon (Eastern Standard or Daylight Time, accordingly)</p><p>NEW MOON FIRST QUARTER FULL MOON LAST QUARTER</p><p> d h m d h m d h m d h m</p><p>JAN. 3 13 57 JAN. 11 12 45 JAN. 19 4 01 JAN. 25 23 01 FEB. 2 0 45 FEB. 10 4 51 FEB. 17 11 14 FEB. 24 2 56 MAR. 3 18 17 MAR. 11 22 54 MAR. 18 22 43 MAR. 25 14 16 APR. 2 13 15 APR. 10 14 04 APR. 17 7 36 APR. 24 2 36 MAY 2 6 09 MAY 10 0 27</p><p>(table from http://aa.usno.navy.mil/)</p><p>To get an idea of what astronomical phenomena (such as planets) may be visible and where to spot them, see http://www.space.com/spacewatch/sky_calendar.html. Part I: Celestial Motion This set of observations can take as little as 6 weeks to complete.</p><p>You are probably aware that the constellations of fall are not the same as those of spring, but can you explain why? If not, these observations will help.</p><p>Choose a bright star, preferably one that is in the southern and that, at the beginning of the project, is located south or southeast at the time of night you plan to observe. Use your planisphere to see whether or not the star will still be visible by the time you are ending your observations. Once you've chosen a star, you can complete this part of the lab one of two ways:</p><p>1. Choose a convenient place from which to view the star. Write down the time at which the star passes directly over a given ground feature (telephone pole, tree, etc.). Its time of closest passage from week to week will directly give you the seasonal rate of motion of the celestial sphere. You must observe from the same spot each time. Observations should be made at least two weeks apart, with a total or 4 observations, and recorded in your observing log. The first observation should be made around midnight to ensure that, throughout the semester, the sky will always be dark by the time you go to see your star.</p><p>2. Choose a time of night to go outside and observe your star (make sure it's late enough that it will be dark throughout the whole semester). Observe the star 4 times at the same time of night, each observation at least 2 weeks apart. Take special note of the altitude and azimuth of the star.</p><p>Record the desired information in the log pages that follow. You don't have to give the latitude and longitude unless you are observing from somewhere other than College Park. The right ascension and declination can be found on your planisphere. Questions</p><p>1. Is the star arriving at the same position in the sky earlier or later as the term progresses?</p><p>2. By how much per day? Show your calculations.</p><p>3. Why does the star's position change over time in this way?</p><p>Part II: Motion and Phases of the Moon This set of observations will take 2 months to complete.</p><p>This part of the lab is meant to give you a better understanding of the Moon's motion around the Earth. If you do this correctly, you will see a pattern in the Moon's phase and position. Observe the Moon at least 10 different nights. The first 5 should be during one lunar cycle, and the second 5 should be during the next lunar cycle. You should have observations spanning the entire cycle – for example, I don't want 5 successive days of the waxing crescent Moon, but instead I'd like to see waxing and waning crescents and gibbouses, and maybe a first/last quarter or a full/new Moon. So, you should space out subsequent observations by about 4-6 days (weather dependent). Another important point: Make one observation in the second set of 5 during an exact same phase that you observed from the previous set of 5. I suggest observing the first quarter, full, or last quarter phase for this. The time it takes the Moon to return to the exact same phase it was a cycle earlier is called the synodic period, and in this way you can determine that length of time. The following data should be recorded in your observing log:</p><p>1. time and date 2. place of observation 3. sky condition 4. phase of Moon 5. sketch of the Moon and the surrounding star field, with any constellations or bright stars labeled</p><p>Do your best to plot the location of the Moon on the star charts provided, and write the date and phase as well. From your plotted positions, you can determine the average number of degrees per day that the Moon moves with respect to the stars. Knowing that there are 360 degrees in one sidereal period, you can now find the sidereal period of the Moon. Phases of the Moon</p><p>Image courtesy of http://starchild.gsfc.nasa.gov February Star Chart This is how the sky will appear at 8:30pm on February 15. Sky chart courtesy of http://www.heavens-above.com.</p><p>March Star Chart This is how the sky will appear at 8:30pm on March 15. Star chart courtesy of http://www.heavens-above.com.</p><p>April Star Chart</p><p>This is how the sky will appear at 8:30pm on April 15. Star chart courtesy of http://www.heavens-above.com.</p><p>Questions</p><p>1. From your plotted positions on the sky chart, you can determine the average number of degrees per day the moon moves with respect to the stars. What is this average number of degrees per day?</p><p>2. There are 360 degrees per sidereal period. Using the information from #1, calculate the lunar sidereal period. (Remember to show your work.)</p><p>3. The time interval between two similar consecutive phases of the moon is its synodic period. According to your observations, what is the synodic period? </p><p>4. Which is longer, the sidereal or synodic period? Why?</p><p>5. The ecliptic is the Sun’s path on the Earth’s celestial sphere. On the celestial sphere, the sun travels through the constellations of the zodiac (Capricornus, Aquarius, Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, and Sagittarius). On a sky chart, the ecliptic looks like a gently curved, smooth line that goes from east to west, roughly through the centers of the zodiac constellations. Draw in the ecliptic.</p><p>6. According to your sky chart, what phase is the moon when it is closest to the ecliptic? What does this imply about the way the Earth, Moon, and Sun are positioned in space during this phase? What phase is the Moon when it is furthest away from the ecliptic? What does this imply about the way the Earth, Moon, and Sun are positioned in space during this phase? (Feel free to use pictures as well as words.) 7. Draw a curve on your star chart where the Moon’s orbit (from your plotted positions) crosses the ecliptic. What is the angle that the Moon’s orbit makes with the ecliptic? What are the implications of this to the frequency of solar and lunar eclipses?</p><p>Part III: Apparent Motion of the Planets These observations will take 2 months to complete.</p><p>The purpose of these observations is to observe and record the apparent positions of selected planets and to determine their apparent motion over a period of time. This semester, Venus and Saturn are visible in the night sky, so use those two planets. The planets appear to move with respect to the stars, a motion which is in addition to the daily sweep of planets, stars, and the Sun across the sky due to the Earth's rotation. This apparent motion of the planets has been studied for centuries. Many attempts have been made to describe this apparent motion. Ptolemy used epicycles and deferents. Copernicus came closer to the correct explanation but also used epicycles. Kepler finally arrived at the correct solution by assuming elliptical orbits. For each planet, you should make 2 observations each month over a 2-month interval (4 observations per planet, about 2 weeks apart). For each observation, record the following:</p><p>1. time and date 2. place of observation 3. sky condition 4. sketch of the planet's position and the surrounding star field, labeling any nearby constellations or bright stars</p><p>Also, do your best to plot the location of each planet on the star charts provided in the following pages. You can use these plots to answer some of the questions at the end. Questions</p><p>1. In which direction, with respect to the stars, did each planet move (same or opposite direction) over the course of the semester?</p><p>2. Was this motion at a constant rate? Elaborate.</p><p>3. Which planet moved fastest, and why?</p><p>4. How far in degrees did each planet move over the course of your observations?</p><p>5. Describe how the Earth's and other planets' actual orbital motion are related to the motions you observed in the sky. Part IV: Independent Observations</p><p>Part of the fun of amateur astronomy is exploring the night sky! Observe 15 constellations, galaxies, nebulae, or other objects of your choosing and record the observations in the following log. At least five of these should be objects that we have not observed in class. You may use observations done during observatory open houses. In your sketches of constellations, indicate the brightness of each star by using different sized dots. If you can tell that a star is a certain color, please note it beside the star. You will get 5 points extra credit for finding each of the following objects, as long as the observation is not done during class (I might point it out during class, but you have to find it again later on your own): Mercury, Mars, Jupiter, Uranus, Neptune, or a comet. Part I: Celestial Motion</p><p>Part II: Motion and Phases of the Moon</p><p>Part III: Apparent Motion of the Planets Part IV: Independent Observations</p>