20180310

Astronomy midterm question: still see three grand constellations low in the west?

Astronomy 210 Midterm 1, spring semester 2018
Cuesta College, San Luis Obispo, CA

An astronomy magazine article[*] describes the positions of constellations in the sky at a certain time of year:
During this month you'll see in the night sky three grand constellations: Canis Major, Orion and Taurus. But being low in the west they'll soon set, so catch them right after sunset while you can.
Discuss a plausible date and time for an observer in San Luis Obispo, CA to make this observation of Canis Major, Orion and Taurus in the sky. If there is no such plausible date and time, then explain why. Defend 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.)

[*] "Sky Maps: December 2017-December 2018," Skywatch (2018), p. 18.

Solution and grading rubric:
  • p:
    Correct. Discussion includes the following:
    1. turns starwheel such that Canis Major, Orion and Taurus are along the low over the west/southwest horizon (or have some or all three constellations partially or already set);
    2. reads off a plausible date corresponding to a time just after sunset (5 PM-8 PM?).
    Has argument on plausibility (or implausibility) that is consistent with these constraints.
  • r:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. May have:
    1. Canis Major, Orion and Taurus located high in the sky; or
    2. picked a time during the night that is not just after sunset (such as midnight).
    Still has argument on plausibility (or implausibility) that is consistent with these misinterpretations of the given constraints.
  • t:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. Typically has both (3) and (4) above, but still has consistent argument on plausibility (or implausibility).
  • 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 30674
Exam code: midterm01nND4
p: 19 students
r: 6 students
t: 0 students
v: 0 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 2123)

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