with
the ecliptic
Please give clear, specific, and unambiguous answers.
Partial credit will be given on Questions 1 and 2, but not on the short-answer questions (unless indicated otherwise).
Each short answer problem is worth 5 points. Fill in the blank, circle the correct answer, etc, as indicated.
1. State what the biggest contributions or achievements were for each of the following figures in the history of astronomy.
(a) (2) Eratosthenes
(b) (2) Aristarchus
(c) (2) Copernicus
(d) (4) Galileo, including several phenomena in astronomy that he discovered
(e) (4) Kepler, including his three laws
(f) (4) Newton, including his law of gravity and the various kinds of orbits that he deduced from this law
(g) (2) Einstein
2. (a) (5) Draw a picture, showing (with labels) the position of the sun, the moon, and the earth during a total eclipse of the moon. (b) (5) Also, show and label the umbra and the penumbra.
3. (5) For a particular telescope, the focal lengths of the objective and the eyepiece are respectively 0.9 m and 0.5 cm. What is the magnification?
Answer: _____________________________
4. (5) How many tides are there per day (at a typical point on the earth), and for what reason? (On each multiple-choice question, circle the correct answer or the letter for the answer. )
four, because the sun and the moon each produce two tides
two, because the sun and the moon each produce one tide
one, because the sun is of dominant importance
one, because the moon is of dominant importance
two, because the sun is of dominant importance
two, because the moon is of dominant importance
none of the above
5. (5) Suppose the separation between two features on the moon is 100 km, and that the moon is 380 000 km from an observer on the earth. What is the angular separation of these two features, as seen by the observer? (Recall that one radian equals 206 265 arc seconds, or 206 265", or just use the formula that employs this fact.)
Answer: ______________________________
6. (5) What type of objects has the Hubble Space Telescope revealed with with more information and detail than ground-based telescopes? Circle all correct answers. (You will receive part of the credit for each correct answer.)
the inner planets
the outer planets
Pluto and its moon Charon
distant galaxies
nebulae
remnants of supernovae
the moon
7. (5) If one telescope has a diameter of 8 m and another has a diameter of 0.5 m, by what factor do their light-gathering powers differ?
Answer: ______________________________
8. (5) We experience seasons because
the axis of rotation of the earth lies in the plane of the ecliptic
the axis of rotation of the earth points toward the zenith
the axis of rotation of the earth points toward the celestial poles
the axis of rotation of the earth is in the plane of the celestial equator
the earth is farther from the sun in summer
the earth is farther from the sun in winter
the axis of rotation of the earth does not make an angle of 90
with
the ecliptic
the axis of rotation of the earth does not make an angle of 0
with
the ecliptic
none of the above.
9. (5) Draw a picture showing the two mirrors, the observers, and the paths of the rays of light for a Cassegrain telescope.
10. (5) If one star is 4th magnitude and another is 9th magnitude, by what factor do their intensities differ?
10
100
1000
10 000
10 
10 
10 
10 
none of the above
11. (5) Suppose that the intensity of light
from star X is 
as large as the intensity of light from star Y. (I.e.,
the ratio of their intensities is , and star X is brighter.) Also suppose that
the magnitude of star X is 3.49. What is the magnitude of star
Y?
Answer: ______________________________
12. (5) What is parallax? Just give a short clear description in your own words.
13. (5) The time required for the moon to make one complete orbit relative the stars (rather than the sun-earth axis) is called a
sidereal period
canonical period
Galilean period
synodic period
peculiar period
Grenwich period
None of the above
14. (5) What is the resolving power of a 2 meter telescope?
5.8 degrees
5.8 arc minutes
5.8 arc seconds
0.058 degrees
0.058 arc minutes
0.058 arc seconds
none of the above
15. (5) List four different kinds of electromagnetic radiation that are used in astronomy. (You will receive part of the credit for each correct answer.)
(i)
(ii)
(iii)
(iv)
16. (5) Why do we not always see a total eclipse whenever we see a full moon? I.e., if the noon is exactly on the other side of the earth from the sun, why is it not completely in the earth's shadow? Explain in your own words.