20171012

Astronomy midterm question: Cassiopeia and Cepheus near the zenith?

Astronomy 210 Midterm 1, fall semester 2017
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board was asked and answered[*]:
JzT: For Cassiopeia and Cepheus, when can you observe both constellations?
GfG: They are at their highest point in the sky in the early evening in early winter.
Discuss why this answer is correct for an observer in San Luis Obispo, CA. Support your answer by clearly explaining how you used your starwheel to do this, along with any assumptions that you may have made. (Ignore daylight saving time.)

[*] answers.yahoo.com/question/index?qid=20150503001213AAzFCuc.

Solution and grading rubric:
  • p:
    Correct. Discussion includes the following:
    1. turns starwheel such that Cassiopeia and Cepheus are at/near the zenith (highest point the in sky), and reads off a plausible early evening time lined up with an early winter (or arguably late fall) date; or
    2. lines up a plausible early evening time with an early winter date, and verifies that Cassiopeia and Cepheus are at/near the zenith.
  • r:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. May actually have Cassiopeia and Cepheus at their lowest possible position in the sky (between Polaris and the north horizon).
  • t:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. ague on time and/or date used for "early evening" and "early winter," may have used a specific time that is arguably not "early evening" (sunrise, midnight, etc.), and/or has Cassiopeia and Cepheus not at their highest possible position in the sky.
  • v:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use starwheel in a systematic manner.
  • x:
    Implementation/application of ideas, but credit given for effort rather than merit. Discussion not clearly based on using a starwheel in a systematic manner.
  • y:
    Irrelevant discussion/effectively blank.
  • z:
    Blank.
Grading distribution:
Section 70158
Exam code: midterm01Sn0w
p: 34 students
r: 4 students
t: 7 students
v: 0 student
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 2622), placing Cassiopeia and Cepheus at the zenith, and finding a plausible date and time:

Another sample "p" response (from student 2137), using a plausible date and time, and finding Cassiopeia and Cepheus at the zenith (while also eliminating other "early season" dates and times):

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