Layna Meyerpeter TrackingMotionsWorksheet (pdf)

Tracking Motions Worksheet These lab activities have evolved over many years of use in Clemson University’s Department of Physics and Astronomy general astronomy laboratory. Contributors include, in chronological order, Tom Collins, Mark Leising, Neil Miller, Peter Milne, Grant Williams, Donna Mullenax, Jessica Crist, Keith Davis, Amber Porter, Steven Bromley, and David Connick. Please direct all questions, complaints, and corrections to David Connick (dconnic@clemson.edu) who is responsible for all errors and omissions. Student Name: ____Layna Meyerpeter____ Section: _Mon 10-11:50am__ The Sun's Yearly Motion: 16th of each month Table 1. Month Constellation Rises (am) (Hour:minute ) Sets (pm) (Hour:minute) Daylight Length (hours) Altitude (above horizon) (degrees Minutes) Jan Sagittarius 7:37 AM 5:44pm 10 hours, 7 mins +34º 26' 08.0" above horizon Feb Aquarius 7:15 AM 6:15 PM 11 hours +43º 01' 49.0" above horizon March Pisces 7:40 AM 7:39 PM 12 hours +53º 42' 21.9" above horizon April Pisces 6:58 AM 8:04 PM 13 hours, 6 mins +65º 37' 16.3" above horizon May Taurus 6:27 AM 8:28 PM 14 hours +74º 31' 41.6" above horizon June Taurus 6:17 AM 8:46 PM 14 hours, 30 mins +78º 40' 22.9" above horizon July Gemini 6:30 AM 8:44 PM 14 hours, 14 mins +76º 29' 43.3" above horizon Aug Leo 6:52 AM 8:18 PM 10 hours, 30 mins +68º 51' 27.7" above horizon Sept Leo 7:15 AM 7:36 PM 12 hours, 12 mins +57º 45' 39.8" above horizon

1. What month is the Sun's altitude a maximum? __June_____ 2. What month is the Sun's altitude a minimum? ____December___ 3. In which month is the length of the day the shortest? ____December_____ 4. In which month is the length of the day the longest? ___June____ 5. Describe the relationship between the altitude and the length of the day. ____Month of June has the highest altitude, so the higher the altitude longer the day.___ 6. During the longest day of the year, what is the distance from the Earth to the Sun in AU? (You will need to set the date based on your table and look at the info panel for the Sun) __In June: 1.015802 AU____ 7. During the shortest day of the year, what is the distance from the Earth to the Sun in AU? (You will need to set the date based on your table and look at the info panel for the Sun) ___In December: 0.984159 AU_______ 8. During lunch, you overhear a group of friends claiming that the cold weather in winter is due to the Earth being furthest from the Sun in its orbit. From your data above, is this claim true? Explain. This is not true because in the winter months because in December the distance is 0.984159 AU which is closet to sun but it is still the coldest time of the time. In June, the distance is 1.015802 AU which is the furthest from sun. So the seasons are based on the tilt not the distance. 9. What is the true cause of the Seasons? (Use the information in your table and your knowledge from ASTR1010, you should mention the sun’s altitude in your answer) The true cause of the Seasons is the tilt of the Earth towards and away from the Sun. In the summer the tilt is towards, with longer days and more sunlight so it is warmer and in the winter the Sun is away, so shorter days and colder weather. 10. Does the Sun spend an equal amount of time in every Zodiacal constellation? Why or why not? (Give examples) (Look at the path of the sun through the constellations, remember the sun moves along the ecliptic at a constant rate.) October Virgo 7:37 AM 6:55 PM 11 hours, 18 mins +46º 09' 21.0" above horizon November Libra 7:06 AM 5:25 PM 10 hours, 19 mins +36º 22' 56.6" above horizon December Ophiuchus 7:31 AM 5:22 PM 9 hours, 51 mins +32º 00' 14.4" above horizon

Orbits and retrograde motion 15. Watch Mercury’s movement relative to the grid lines carefully (You can click on Mercury center on it to better see its motion relative to the grid lines), during what time period does Mercury appear to move backwards (to the west)? (This is retrograde motion) Mercury appears to be moving backwards in mid June. 16. Now search for and center on the Moon. Does the Moon travel precisely along the ecliptic (always touch the ecliptic line)? Explain its motion relative to the ecliptic line. The moon does not travel precisely along the ecliptic line. It is always relatively close but never directly on it. On March 23rd 2020 the moon is close to the sun and a grid line. Set the time and date to see this in Starry Night. Search for and lock on the Sun then prepare to step time forward and answer the next questions. 17. How long does it take for the moon to return to the same grid line? (this is called the sidereal period) It took the moon about 28 days to return to the same grid line. (Apr. 20th) 18. How long does it take for the moon to get close to the sun again? (this is called the synodic period) It took the moon about 30 days to get close to the sun again. (Apr. 22nd) 19. What is the difference in time for the moon to return to the same grid line (background stars) to the time it takes to return close to the sun? The difference is 2 days. 20. When viewed from above the north pole, which direction does the Earth orbit the sun, and which direction does the moon orbit the earth? (think back to ASTR1010) The Earth orbits the sun counterclockwise and the moon orbits the Earth counterclockwise. 21. Do your best to explain the connection between the orbit directions as viewed from above and how we see the sun and moon move in the sky relative to the background stars (grid lines) from the surface of the Earth. Earth is moving West to East, so the stars appear to move East to West from the surface of the Earth.