20141011

Astronomy midterm question: summer coming when Scorpius rises in morning?

Astronomy 210 Midterm 1, fall semester 2014
Cuesta College, San Luis Obispo, CA

An astronomy article[*] discusses how the constellation Scorpius can be used as a sign of the changing seasons:
I once heard Edwin Hubble remark, "Well, summer is on the way. I saw Scorpius rising this morning."
Discuss a plausible date and time for an observer in San Luis Obispo, CA to make this observation of Scorpius a signal that "summer is on the way." 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.

[*] G. Purdam; R.S. Richardson "Naked Eye Objects: Your Favorites?" The Griffith Observer, Vol. 44, No. 8 (August 1980), p. 23, books.google.com/books?id=Y_vxAAAAMAAJ.

• p:
Correct. Discussion arguing for plausible date/time for Scorpius rising in the morning to signal the start of summer includes the following:
1. manipulates starwheel (planisphere) such that Scorpius is rising from the eastern horizon;
2. chooses a plausible "morning" (but still dark) time (12 AM to 6 AM) to view stars;
3. chooses a corresponding month that would plausibly be soon before the start of summer.
However, if "rises in the morning" is strictly applied to sunrise or just before sunrise, then Scorpius is found to be rising during December/January, in which case student may either argue for plausibility (just past winter solstice, so days will get longer advancing towards the summer solstice) or implausibility (middle of winter).
• r:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Diagram and/or explanation has minor errors. Problems with one of the three discussion points in (p); may have Scorpius transiting or high overhead; may pick a daytime hour; or may pick a month that is not soon before the start of summer. Or intends "rises in the morning" to be taken as sunrise, but instead picks a time well after sunrise.
• t:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. Problems with diagram or discussion; has only one of the three discussion points in (p).
• v:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Some related discussion of starwheel use, morning times, and seasons.
• x:
Implementation/application of ideas, but credit given for effort rather than merit.
• y:
Irrelevant discussion/effectively blank.
• z:
Blank.
Section 70158
Exam code: midterm01neVs
p: 22 students
r: 15 student
t: 6 students
v: 2 students
x: 0 students
y: 0 students
z: 0 students

Section 70160
Exam code: midterm01s4Tn
p: 20 students
r: 2 students
t: 4 students
v: 6 students
x: 4 students
y: 0 students
z: 0 students

A sample "p" response (from student 7809), finding for plausibility:

A sample "p" response (from student 1770), arguing for implausibility:

A sample "r" response (from student 2125), placing Scorpius at its highest point in the sky:

A sample "r" response (from student 3566), placing Scorpius low over the west horizon instead of the east horizon:

A sample "t" response (from student 5656), placing Scorpius in its highest point in the sky at noon: