## 20140208

### Astronomy quiz question: diurnal motion of sun versus zodiac constellations

Astronomy 210 Quiz 1, spring semester 2014
Cuesta College, San Luis Obispo, CA

[Version 1]
The diagram at right shows positions of constellations and the sun, as seen at 12:00 PM by an observer in San Luis Obispo, CA. Ignore daylight saving time. Assume you can see stars in daylight. Which will set first on this date?
(A) The sun.
(B) Sagittarius.
(C) (There is a tie.)
(D) (Neither will set, as they are circumpolar.)

Correct answer (highlight to unhide): (A)

Generally objects low in the southern sky, located to the east of the meridian will set after objects that lie on or towards the west of the meridian. (This can be demonstrated using a planisphere (starwheel) for Sagittarius and Scorpius, as the sun would take approximately one month to move to the next zodiac constellation, and will remain within Scorpius during this date.)

Section 30674
Exam code: quiz01nYe3
(A) : 11 students
(B) : 6 students
(C) : 10 students
(D) : 3 students

Success level: 38% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.43

[Version 2]
The diagram at right shows positions of constellations and the sun, as seen at 12:00 PM by an observer in San Luis Obispo, CA. Ignore daylight saving time. Assume you can see stars in daylight. Which will set first on this date?
(A) The sun.
(B) Libra.
(C) (There is a tie.)
(D) (Neither will set, as they are circumpolar.)

Correct answer (highlight to unhide): (B)

Generally objects low in the southern sky, located to the west of the meridian will set before objects that lie on or towards the east of the meridian. (This can be demonstrated using a planisphere (starwheel) for Scorpius and Libra, as the sun would take approximately one month to move to the next zodiac constellation, and will remain within Scorpius during this date.)

Section 30676
Exam code: quiz01SLo3
(A) : 7 students
(B) : 32 students
(C) : 5 student
(D) : 1 student

Success level: 73% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33