Astronomy midterm question: Auriga, Gemini, and Leo in early evening sky

Astronomy 210 Midterm 1, fall semester 2019
Cuesta College, San Luis Obispo, CA

An astronomy magazine article describes the positions of constellations in the night sky at a certain time of year[*]:

Early in the evening, Auriga and Gemini are high in the sky, while Leo, the Lion, stands at attention about halfway up the sky.

Discuss a plausible date and time for an observer in San Luis Obispo, CA to make this observation of Auriga, Gemini, and Leo in the early evening 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 2018-December 2019," Skywatch (2019), p. 18.

Solution and grading rubric:

• p:
  Correct. Discussion includes the following:
  1. locates the constellations Auriga and Gemini on the starwheel, and rotates starwheel such that both are at or near the zenith (Leo will then be visible somewhere between the zenith and the eastern horizon); and
  2. selects a time that is dark enough to see stars in the early evening (somewhere between 7 PM and 10 PM or so); and
  3. looks up the date (March/April) corresponding to that early evening time.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Places Auriga and Gemini at the zenith, but discusses December at 12 AM or June at 1 PM as an "early evening" time, or has March/April but does not explicitly choose a time.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Finds a plausible date and evening time (or discusses that this would be impossible) when Auriga and Gemini are low in the west horizon, with Leo high 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: midterm01Sw3e
p: 19 students
r: 6 students
t: 9 students
v: 2 students
x: 0 students
y: 0 students
z: 0 students

Section 70160
Exam code: midterm01N0dL
p: 7 students
r: 3 students
t: 11 students
v: 2 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 2120):