Astronomy midterm question: Sagittarius as both sun-sign and rising-sign?

Astronomy 210 Midterm 1, spring semester 2017
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board was asked and answered[*]:

NSt: I recently went to see an astrologer in my town, and was told that that my sun-sign is Libra and my rising sign is Aquarius. Anyways, is that wrong? If you want to figure it out, I was born 12/25 at 8:30 AM.
ArZ: It looks to me like you are clearly both a Sagittarius sun-sign with a Sagittarius rising sign.

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. Assume you can see stars in daylight.)

[*] answers.yahoo.com/question/index?qid=20080921194418AAO10gc.

Solution and grading rubric:

• p:
  Correct. Discussion includes the following:
  1. confirms that Sagittarius is the sun-sign for a 12/25 birthday by finding that it is on the meridian at 12 PM on that day (where the sun also be located); and
  2. confirms that Sagittarius is the rising sign, as it is rising on the east horizon at 8:30 AM on 12/25.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Only has correct verification of sun-sign or rising-sun only.
• 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: midterm01nghT
p: 16 students
r: 0 students
t: 6 students
v: 1 student
x: 0 students
y: 0 students
z: 0 students

Section 30676
Exam code: midterm01sP4m
p: 35 students
r: 4 students
t: 5 students
v: 0 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 1988): Another sample "p" response (from student 9449):