Astronomy 100 -- Problem Set 2
Due: Thursday 14 February 2008
Name:

Fill in the box with the correct answer (answers should be just a few words or a number).

  1. The angular diameter of the Moon is 1/2o = 30 arcminutes = 1800 arcseconds. A penny is approximately 2 centimeters in diameter. How far away from your eye must you hold a penny in order for it to subtend the same angular diameter as the Moon?

  2. The Earth has a diameter of 12700 km. The Moon's diameter is 3500 km. What is the angular size of the Earth as seen by an astronaut standing on the Moon? You don't need to know the distance between the Moon and Earth to solve this problem, since you already know the angular size of the Moon as seen from the Earth from the question above.

  3. If the constellation Andromeda is overhead at midnight tonight, what time will it be overhead one month from now?

  4. On what day of the year is the noontime Sun directly overhead for observers at latitude 23.5 degrees north of the equator?

  5. Which is brighter? a 3rd magnitude star or an -2nd magnitude star?

  6. What is the magnitude of a star that is 100 times fainter than a 4th magnitude star?

  7. At approximately what time does the last quarter Moon rise?

  8. What is the phase of the Earth as seen from the Moon when the Moon is Full?

  9. Suppose the length of the year were 365.2000 days. How often would we have leap years in our calendar?

  10. In a sentence or two, explain the difference between annular and total solar eclipses.