Astronomy midterm question: Great Square and Big Dipper just after sunset

Astronomy 210 Midterm 1, spring semester 2020
Cuesta College, San Luis Obispo, CA

An online astronomy magazine article describes the positions of the "Great Square" (located between the constellations Andromeda and Pegasus) and the Big Dipper just after sunset:[*]:

After dark now the Great Square [between Andromeda and Pegasus] is declining low in the west, tipped onto one corner. Meanwhile the Big Dipper is creeping up in the northeast, tipped up on its handle.

Discuss a plausible date and time for someone in San Luis Obispo, CA to make this observation of the Great Square and the Big Dipper 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.)

[*] skyandtelescope.com/observing/sky-at-a-glance/.

Solution and grading rubric:

• p:
  Correct. Discussion includes the following:
  1. locates the Great Square and the Big Dipper asterisms on the starwheel, and rotates starwheel such that the Great Square is just above the west horizon, while the Bigger Dipper is near the northeast 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 a specific date corresponding to that early evening time.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. May have selected midnight, sunrise or some other time of night not convincingly "after dark," "just after sunset" or an "early evening" time.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. May have Great Square near east horizon, and Big Dipper near the west horizon.
• 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: midterm01n7in
p: 21 students
r: 5 students
t: 3 students
v: 1 student
x: 0 students
y: 0 students
z: 0 students

Section 30676
Exam code: midterm01S7wY
p: 27 students
r: 11 students
t: 2 students
v: 3 students
x: 2 students
y: 0 students
z: 0 students

A sample "p" response (from student 2020):