Astr 2100 Descriptive Astronomy
Samples Questions for Test 1


  1. What physical property of the Earth is responsible for the seasons? The tilt
  2. What is the angle between the line connecting the Earth to the Sun and that connecting the Earth to the Moon if the Moon is in the 1st quarter phase? 90º
  3. Which phase of the Moon corresponds to a Solar eclipse? new
  4. Which phase of the Moon corresponds to a Lunar eclipse? full
  5. What is the declination of the Pole Star? 90º
  6. What are the Right Ascensions and declinations of the two points where the ecliptic and celestial equator cross?
    1. RA = 0º decl = 0º
    2. RA = 180º (or 12 h) decl=0º
  7. Which is furthest from us, the next closest planet, the next closest star, or the next closest galaxy? the next closest galaxy
  8. If you stand on the equator, whereabouts in the sky would you find the North Celestial Pole? the northern horizon
  9. If you stand on the Earth's North Pole, whereabouts in the sky would you find the North Celestial Pole? directly above you
  10. Because of the rotation of the Earth once every 24 hours any star in the sky appears to move from east to west. By what angle does it move in five minutes? 1.25º
  11. Which is the closest star to the Earth? Our own Sun
  12. If you see a full moon rising on March 21st, what time is it? sunset, 6 pm
  13. If you were to see the Moon due south of your at 9 pm tonight, at what time will it be when the Moon is due south of you tomorrow? 9:48 pm
  14. At what time of the day or night would you be most likely to see a lunar eclipse? any time during the night
  15. What is the point in the sky which is directly above you called? zenith
  16. If you observe the Sun directly above you on the date of the Summer Solstice, where are you? anywhere on the Tropic of Cancer
  17. Where in the sky is the star Polaris for an observer in Rio de Janeiro? it isn't, it's below the horizon.
  18. Turlock is located at a latitude of 37½o N. What is the declination of the most southerly star we can see on at least one night of the year? -52½o
  19. Turlock is located at a latitude of 37½o N. What is the declination of the most southerly star we can see on every night of the year? +52½o
  20. Turlock is located at a latitude of 37½o N. What is the altitude of the Sun at noon on the date of the Summer Solstice? 90-37½o+23½o= 76o
  21. Turlock is located at a latitude of 37½o N. What is the altitude of the Sun at noon on the date of the Winter Solstice? 90-37½o-23½o= 29o
  22. Turlock is located at a latitude of 37½o N. What is the altitude of the Sun at noon on the date of one of the equinoxes? 90-37½o= 52½o
  23. What is the ecliptic?
    1. from the sun's POV, the plane of the Earth's orbit
    2. from the Earth's point of view, the arc traversed by the Sun across the sky
  24. List, in order, all of the phases of the Moon.
    1. New
    2. Waxing crescent
    3. First quarter
    4. Waxing gibbous
    5. Full
    6. Waning gibbous
    7. Third quarter
    8. Waning crescent
    9. New
  25. You see a full moon directly overhead. What time is it? midnight
  26. You see a full moon on the western horizon. What time is it? sunrise, 6 am
  27. Excluding the Earth, on how many planets has man set foot? none
  28. Excluding the Earth, on how many planets has we landed a spacecraft? 2 (Venus and Mars)
  29. How far is one light year? Give both a definition and the distance in miles. Distance that light travels in one year = 5.88 x 1012 miles
  30. How far is one astronomical unit? Give both a definition and the distance in miles. Distance between Earth and Sun = 9.3 x 107 miles
  31. If a star is 100 light years from us, how long does it take light to get from this star to us? surpassingly enough, 100 years
  32. What is the Earth's orbital speed around the Sun? 2 * pi * r / T equal to about 64,000 mph
  33. If it is 2 x 1015 miles (about 300 light years) to a star, and you can travel at 6 x 105 mph, how many years would it take you to get there?
    1. 2 x 1015 miles / 6 x 105 mph = 3.3 x 109 hours = 380,000 years
  34. If the Moon is between the Earth and the Sun, which phase do we see? New
  35. What do you see if the Moon passes into the shadow of the Earth? Lunar eclipse
  36. What is the approximate date of the autumnal equinox? Sept 21
  37. What is the approximate date of the winter solstice? Dec 21
  38. In the middle of summer where does the Sun set? north of the western point on the horizon.
  39. During a single night, which way does the Moon move across the sky, and why? east to west because of rotation of the Earth
  40. From night to night, which way does the Moon move across the sky, and why? west to east because of Moon's orbit around the Earth
  41. Which day has the longest daylight period in Australia? Dec 21
  42. What is a constellation? An arbitrary collection of stars which can be imagined to outline a picture. No physical significance.
  43. What does the term solstice mean? Sun static
  44. What does the term equinox mean? Equal night
  45. Despite the beliefs of the flat earth proponents, even the ancients knew that the Earth was round? How did they know this? (might need a little research) Shadow of Earth on Moon during a lunar eclipse is always circular.
  46. Why are the time zones on the Earth separated by 15o? (Ignore political divisions.) Earth rotates 360o in 24 hours. 360/24 = 15
  47. The longitude of Moscow is -37o 35'. What is the longitude of a city where the Sun rises exactly 6 hours later?
    1. 6 hours is equivalent to 90o
    2. since sun is rising later need to go west (that is add 90o)
    3. -37o 35' + 90o = +52o 25'
  48. The latitude of Rome, Italy is 42º N. For an observer there
    1. what is the declination of the most southerly star which can be seen every night of the year? +48o
    2. what is the declination of the most northerly star which can not be seen on any night of the year? -48o