Astronomy midterm question: early evening winter Big Dipper

Astronomy 210 Midterm 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:
dennispatterson58: Can you tell me where to look in the sky to see the Big Dipper? What time in the [early] evening, during [winter], would the Big Dipper become visible to me?
kris: [I]n the early evening, the Big Dipper is low in the...northeast, so if you have a lot of trees along your northern horizon you might have a hard time spotting it.
Discuss whether or not this answer is plausible for an observer in San Luis Obispo, CA. Defend your answer by clearly explaining how you used your starwheel to do this, along with any assumptions that you may have made.

*Source: http://answers.yahoo.com/question/index;_ylt=AhGRV4wgxwhrNmdIGvGLDNYjzKIX;_ylv=3?qid=20061104160752AAKBaSJ.

Solution and grading rubric:
  • p = 20/20:
    Correct. Clearly explains how the Big Dipper being obscured by trees along the north/northeast horizon is plausible. Specifically chooses a plausible "winter" month and "early evening" time on the starwheel and finds position of the Big Dipper, or instead places the Big Dipper above the north/northeast horizon, and finds that a plausible "winter" month lines up with an "early evening" time.
  • r = 16/20:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Only general (as opposed to specific) date, time or position in sky described.
  • t = 12/20:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. Only general information given for at least two out of the three: date, time, position, but still demonstrates use and understanding of starwheel.
  • v = 8/20:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Discussion not based on use of starwheel, but on some understanding of celestial sphere motions.
  • 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:
Grading distribution:
Section 30674
Exam code: midterm01neE7
p: 19 students
r: 9 students
t: 3 students
v: 1 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 1449):

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