Download Astronomy Assignment #1

Astronomy Assignment #2: The Celestial Sphere and The Apparent Motion of
the Stars and Sun
Your Name______________________________________
Your Class Meeting Time __________________________
This assignment is due on __________________________
Submit this cover sheet with your assignment.
Complete the assigned problems from the text listed below and address the Instructor Assigned Topic.
Mathematical problems may be hand written. Write out the problem, show your work in solving the problem
and state your answer in a complete sentence. Failure to complete all three of these tasks will result in less
than full credit awarded. The Instructor assigned topic must be typed.
Text Problems: Answer the following Review Questions from Nick Strobel’s AstronomyNotes: Chapter 3:
Astronomy Without a Telescope
1.
2.
3.
4.
How does the position of the celestial equator, depend on the latitude of the observer?
What angle does the stars nightly path make with respect to the eastern and western horizons?
What reference point is a celestial object on when it is at its highest position above the horizon?
Why do observers in the northern hemisphere see celestial objects north of the celestial equator for more
than 12 hours?
5. For northern hemisphere observers, which celestial object would be above the horizon for the greatest
amount of time: one that is on the celestial equator, one that is 30° above the celestial equator, one that is
70° above the celestial equator, or one that is 40° below the celestial equator? Which one would be
above the horizon the greatest amount of time for southern hemisphere observers? Explain your answer.
6. How does the Sun move with respect to the stars during the day? ...during the year?
7. Why does everyone have 12 hours of daylight on the equinoxes?
8. Why is the length of daylight in the northern hemisphere so short on December 21?
9. When will the Sun be at its highest altitude in the year in Los Angeles or Seattle? How about Singapore
(on the Equator)? Why?
10. On what date is the Sun above the horizon the shortest amount of time for the Southern Hemisphere?
Why?
11. At what two azimuths does the celestial equator intercept the horizon?
12. Why do astronomers prefer using right ascension and declination as opposed to using altitude ad
azimuth?
13. What is the azimuth of any object when it crosses the meridian at any time of year in the southern sky?
14. What is the Sun's altitude on June 22 when it crosses the meridian in Syracuse, NY (+43 N).
15. What is the altitude of the NCP at Fairbanks, Alaska (lat. = 65° N)?
16. What is the maximum altitude of the Sun on the spring equinox for people on the equator? What is the
Sun's azimuth and right ascension at that time?
17. What will the Sun's declination be on the following dates: June 21, March 21, September 22, and
December 21?
18. If the Sun sets 10° away from due West on October 20, what is the sunset azimuth?
19. If the Sun rises 12° away from due East on April 19, what is the sunrise azimuth?
20. What causes precession?
21. Which star is the current pole star? Which star was the pole star 2,000 years ago? Which star will be the
pole star 8,000 years from now?
22. Why is there a difference between the sidereal day and solar day?
Instructor Assigned Topic:
Sketch the apparent motion of the stars, following the example in class, looking in the four cardinal directions
(N, E, S & W) for the following four locations: The North Pole (90 N), Syracuse, NY (43 N), The Equator (0
N), Punta Arenas, Chile (53 S). Include all relevant timescales (time for stars to complete once cycle and time
that stars are above the horizon) and all relevant angles (altitude of Polaris, declination of the circumpolar
boundary, slant angle of rising and setting stars looking east and west, declination of the southern (or northern)
most visible star).
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