_TrackingMotionsWorksheetPDF

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: __Izabella Romero Rainey _______________________________ Section: _______ The Sun's Yearly Motion Table 1. Month Constellation Rises (am) (Hour:min ute ) Sets (pm) (Hour:minute ) Daylig ht Lengt h (hours) Altitude (above horizon) (degrees Minutes) January Sagittarius 7:39am 5:35pm 10 +32degrees 51’ 04.2” February Capricornus 7:25am 6:05pm 11 +39 degrees 39’ 42.7” March Aquarius 6:45am 6:31pm 12 +49degrees 39’ 01.8” april Pices 7:11am 7:56pm 13 +61degrees 32’ 45.8” May Aries 6:36am 8:20pm 14 +71degrees 55’ 29.7” June Taurus 6:18am 8:42pm 14 +77degrees 59’ 52.3” July Gemini 6:24am 8:47pm 14 +77degrees 54’ 12.3” August Cancer 6:45am 8:29pm 14 +71degrees 52’’ 14.1” September Leo 7:07am 7:51pm 13 +61degrees 40’ 00.6”

October Virgo 7:29am 7:08pm 12 +50degrees 02’ 17.9” November Libra 6:56am 5:33pm 11 +39degrees 09’ 28.8” December Ophiuchus 7:24am 5:20pm 10 +32degrees 47’ 38.3” 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. The altitude of the sun correlates with how much daylight there is. The higher the altitude the longer the day light and vise versa with lower altitude and less daylight. _____________________________________ 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) 1.016216AU____________________ 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) _0.983737AU___________________ 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 it has more to do with the altitude and tilt of the sun and how it relates to earth. 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 how the earth's spin axis is tilted with respect to the orbital place around the sun. Summer is caused by the tilt when the altitude is highest

14. Based on what you see in the table and what you know about the planets, why do some objects have greater changes in position than others? (Recall how distance from the sun affects the orbital rate of planets) Some objects have greater change in position than others because the object's mass is different, thus affecting the force needed to achieve the change in motion. Return to the instruction document to set up the next simulation before answering the next set of questions. 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 move backwards towards the west between mid december and early january 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 precisely travel along the ecliptic. Starting around mid april and march the moon begins to travel off the ecliptic slightly. 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 takes about a month (around april 22) for the moon to return to the same grid line 18. How long does it take for the moon to get close to the sun again? (this is called the synodic period) It takes about three months (around june 21) for the moon to get close to the sun again 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? It takes about five months (around november 14) for the moon to return to the same grid line 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 orbit appears to be going counter clockwise when viewed from above the north pole 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. Since the rotation is from west to east, to us it appears that the moon and sun in relativity to the background stars move from east to west. 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: _________________________________ Section: _______ The Sun's Yearly Motion Table 1. Month Constellation Rises (am) (Hour:min ute ) Sets (pm) (Hour:minute ) Daylig ht Lengt h (hours) Altitude (above horizon) (degrees Minutes)

Date: Date: Object RA Dec RA Dec Venus Jupiter 11. All of the planets deviate very little from the ecliptic plane. Therefore, their declination may not change all that much. Which planet had the larger change in declination and by how much did it change? 12) However, an object is much more likely to have a greater change in right ascension throughout the year. Which object shows the greatest apparent change in right ascension over 2 months and by how much did it change? 13. Is the planet that is close to the Sun (i.e. Venus) changing its RA faster or slower than the planet further from the sun (i.e. Jupiter)? (support your answer with numbers) 14. Based on what you see in the table and what you know about the planets, why do some objects have greater changes in position than others? (Recall how distance from the sun affects the orbital rate of planets) Return to the instruction document to set up the next simulation before answering the next set of questions. 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) 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. 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)

18. How long does it take for the moon to get close to the sun again? (this is called the synodic period) 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? 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) 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.