20081013

Astronomy midterm question: the "West Star"

Astronomy 210 Midterm 1, fall semester 2008
Cuesta College, San Luis Obispo, CA

[20 points.] Shown at right is an excerpt from a comic strip* printed on June 24, 1970. Discuss whether or not there is such a thing as a "West Star" that can be used for navigation. Defend your answer by clearly explaining how you used a starwheel to determine this.

*Peanuts, Charles M. Schulz, ©United Features Syndicate, Inc.

Solution and grading rubric:
  • p = 20/20:
    Correct. Discusses why there would be no "West Star," as over the course of an evening, all non-circumpolar stars rise from the east, move across the sky, and set in the west, such that a given star that was near the west horizon would set below the horizon. May instead argue for a temporary "West Star" that can be used for navigation, given a starwheel and the date/time.
  • r = 16/20:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
  • t = 12/20:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors.
  • v = 8/20:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
  • x = 4/20:
    Implementation/application of ideas, but credit given for effort rather than merit.
  • y = 2/20:
    Irrelevant discussion/effectively blank.
  • z = 0/20:
    Blank.
Grading distribution:
Section 70160
p: 25 students
r: 3 students
t: 4 students
v: 0 students
x: 1 students
y: 0 student
z: 1 students

A sample "p" response (from student 2639):A more elaborate "p" response (from student 4731):
A "p" response (from student) arguing how a "West Star" (albeit, a temporary one) can be used for navigation:

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