20171012

Astronomy midterm question: Cassiopeia and Cepheus east of Polaris?

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?
CAk: After sunset late in the summer, they will be located east of Polaris.
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 east of Polaris, and reads off a plausible time around or just after sunset lined up with a late summer date; or
    2. lines up a plausible time around or just after sunset with a late summer date, and verifies that Cassiopeia and Cepheus east of Polaris.
  • 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), or at their highest possible position in the sky (near the zenith).
  • t:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. Vague on time and/or date used for "after sunset" and "late summer," may have used a specific time/date that is arguably neither, and/or has Cassiopeia and Cepheus not located east of Polaris.
  • 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 70160
Exam code: midterm01nDm3
p: 29 students
r: 2 students
t: 1 student
v: 1 student
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 1352), placing Cassiopeia and Cepheus east of Polaris, and finding a plausible date and time:

Another sample "p" response (from student 3432), using a plausible date and time, and finding Cassiopeia and Cepheus east of Polaris:

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