Exercise - I. 1. The point in the sky that is located 90 degrees above the horizon is the

Transcription

1 Exercise - I 1. The point in the sky that is located 90 degrees above the horizon is the a) terrestrial horizon b) equator c) pole d) zenith e) ascending node 2. Which of the following would be the coordinates of a star that is rising in the southeast? a) azimuth 180 degrees, al:tude 0 degrees b) azimuth 180 degrees, al:tude 90 degrees c) azimuth 145 degrees, al:tude 0 degrees d) azimuth 60 degrees, al:tude 0 degrees e) azimuth 75 degrees, al:tude 90 degrees 3. The equivalent of terrestrial longitude in the equatorial (celesgal) coordinate system is a) declina:on. b) the horizon. c) precession. d) right ascension. e) space.

2 4. Where on the Earth does the celesgal equator pass through the zenith? a) Marburg b) the North Pole c) the South Pole d) the equator e) nowhere on Earth 5. The Sun's path on the celesgal sphere is a) the zenith. b) the equator. c) the meridian. d) the eclip:c. e) the yellow brick road. 6. The occurrence of seasons on the Earth results from a) the Earth being closer to the Sun in summer. b) the Earth changing its rota:on rate during the year. c) the Earth's axis poin:ng in different south and then north during the year. d) the Earth's axis being inclined to the eclip:c. e) the appearance of Sirius rising above the Nile.

3 7. Where is the Sun on December 21? a) RA = 0 h, Dec = 0 o b) RA = 6 h, Dec = 23.5 o c) RA = 6 h, Dec = 23.5 o d) RA = 18 h, Dec = 23.5 o e) RA = 18 h, Dec = 23.5 o 8. Greenwich mean Gme or universal Gme is the standard Gme for longitude? a) 90 degrees b) 45 degrees c) zero degree d) 180 degrees 9. If we take an apple, assume it is a sphere, and cut it in half; we slice through a great circle. If we make a mistake, miss the center and hence cut the apple into two unequal parts we will have sliced through a a) great circle b) spherical angle c) small circle d) prime meridian

4 10. If the plane does not contain the center of the sphere, it is known as a) Greenwich meridian b) great circle c) small circle d) principle vertex 11. Which of the following statements about the celesgal sphere is not true? a) The celes:al sphere is just another name for our universe. b) From any loca:on on earth, we can see only half the celes:al sphere at any one :me. c) When we look in the sky, the stars all appear to be located on the celes:al sphere. d) The earth is placed at the center of celes:al sphere. e) The celes:al sphere does not exist physically. 12. Which of the following statements about the celesgal equator is true at all lagtudes? a) It extends from your horizon due east, through your zenith, to your horizon due west. b) It lies along the band of light we call the milky way. c) It cuts the dome of your sky exactly in half. d) It represents an extension of earth s equator onto the celes:al sphere. e) It extends from your horizon due north, through your zenith,to your horizon due south.

5 13. Which of the following correctly describes the meridian in your sky? a) A half- circle extending from your horizon due north, through your zenith, to your horizon due south. b) A half circle extending from your horizon due east, through your zenith, to your horizon due west. c) A half circle extending from your horizon due east,through the north celes:al pole,to your horizon due west. d) The boundary between the por:on of the celes:al sphere you can see at any moment and the por:on that you cannot see. 14. You are standing on the earth s equator. Which way is Polaris, the North star? a) Directly overhead. b) 30 degrees up, due west. c) On the northern horizon. d) The answer depends on whether it s winter or summer. e) The answer depends on what :me of day (or night) it is. 15. What is eclipgc? a) The sun s apparent path along the celes:al sphere. b) The moon s apparent path along the celes:al sphere. c) The sun s daily path across the sky. d) When the moon passes in front of sun.

6 16. What is a circumpolar star? a) A star that makes a daily circle around the celes:al sphere. b) A star that is visible close to the north celes:al pole. c) A star that always remains above your horizon. d) A star that is close to the south celes:al pole. 17. DeclinaGon is measured from a) Horizon b) prime meridian c) celes:al equator d) zero point 18. For a star what remains the same for all Gmes? a) Azimuth b) hour angle c) right ascension d) declina:on

7 19. Parallax would be easier to measure if a) Earth's orbit were larger. b) the stars were farther away. c) Earth moved faster along its orbit. d) all of these e) none of these 20. If a star has a parallax of 0.02 seconds of arc, then its distance is a) 20 pc b) 50 pc c) 2 pc d) 5 pc e) 500 pc 21. Suppose you measure the parallax angle for a pargcular star to be 0.1 arc second. The distance to this star is a) 10 light-years. b) 10 parsecs. c) 0.1 light-year. d) 0.1 parsec. e) impossible to determine.

8 22. Suppose that you measure the parallax angle for a pargcular star to be 0.5 arc-second. The distance to this star is a) 0.5 light-year. b) 0.5 parsec. c) 5 light-years. d) 5 parsecs. e) 2 parsecs. 23. The most distant stars we can measure stellar parallax from Earth are approximately a) 50 parsecs away. b) 500 parsecs away. c) 5,000 parsecs away. d) halfway across the Milky Way Galaxy. e) in the Andromeda Galaxy. 24. A star with a parallax angle of 1/20 arc-second is a) 20 light-years away. b) 1/20 parsec away. c) 20 parsecs away. d) 10 parsecs away.

9 25. Suppose you are at the equator which has a lagtude of 0 0. The algtude of the north celesgal pole as seen from your posigon is a) 90 0 b) c) d) 0 0 e) 45 0

10 6. At la:tude of 50 0 N, a star has a declina:on =30 0 N. Find it s zenith distance when it s on observer s meridian. Answer: Zenith Distance = 20 0

11

12

13

14

15 500

16

17

18

19

20 Zenith Distance

21 Zenith Distance = 20 0

22 LaGtude = 50 0, DeclinaGon = 30 0 AlGtude = Dec + ( AlGtude of NCP); AlGtude of NCP = LaGtude of observer = AlGtude = = Zenith distance = AlGtude = = 20 0