ASTR 110L

Fall 2009

Moon Phases Observing — Follow-up Questions

 

1. (1 pt.)  On the Alt-Az Chart, did the Moon appear to move generally eastward or westward over the course of your observations? 

2. (1 pt.)  On the All-Sky Star Chart, did the Moon appear to move generally eastward or westward over the course of the your observations? 

3. (1 pt.)  On the “Top View” of the Moon’s Orbit (where you plotted the Moon’s approximate position in its orbit for each of your observation dates), does the Moon orbit around the Earth eastward or westward?  Does this agree with your answers to questions (1) & (2)?  If not, why do you think not? 

 

4. a. (1 pt.)  Using either your All-Sky or Alt-Az chart, estimate the number of degrees that the Moon moves in one day (relative to “stationary” landmarks or background stars/constellations).  You can do this in any way that you wish, but be sure to explain your method. 

b. (1 pt.)  Knowing that the Moon takes 27.3 days to complete 360˚ of its orbit, calculate the number of degrees we should expect the Moon to move each day.  Does this match your measurement in part (a)? 

 

 

 

(3 pts.)  Since you made your observations in the evening, the Sun had set over the western horizon just an hour or two earlier.  The direction of sunlight, therefore, consistently came from just under our western horizon during each observation. 

5.  On the Alt-Az Chart, in which direction did the illuminated part of the Moon face?  Was it always toward the western horizon?  Is this what you would expect?  Briefly explain. 

6.  On the All-Sky Star Chart, in which direction did the illuminated part of the Moon face?  Was it always toward the western horizon?  Is this what you would expect?  Briefly explain. 

 

 

 

On March 18, 2007 (HST), as the Moon is New, there will be a solar eclipse!  Sadly, the few brief hours of eclipse will occur while Asia will be facing the Sun (morning in Asia, during nighttime in the Pacific), so it will not be visible from Hawaii. 

7.  (2 pts.)  Does every New Moon “eclipse” the Sun?  If not, explain why not, and explain approximately how often a New Moon does successfully pass in front of the Sun. 

 

There will also be a lunar eclipse for a few hours surrounding the fullest Full Moon on March 3, 2007… again, sadly, not visible from Hawaii.  (It will be midday in Hawaii when the eclipse happens, when the Full Moon is far below the ground.) 

8. (2 pts.)  Does every Full Moon get eclipsed by the Earth’s shadow? If not, explain why not, and explain approximately how often the Full Moon does get successfully eclipsed the Earth’s shadow.