20100205

Astronomy quiz question: diurnal motion of circumpolar constellation

Astronomy 210 Quiz 1, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

[Version 1]
The constellation Cepheus is located below the star Polaris and just above the north horizon, as seen by an observer on February 3 in San Luis Obispo, CA. (Ignore the fact that your starwheel does not include daylight saving time.) Within the next 24 hours, this observer will notice that the constellation Cepheus:
(A) moves clockwise around Polaris, and never sets below the horizon.
(B) moves counterclockwise around Polaris, and never sets below the horizon.
(C) moves clockwise around Polaris, and sets below the horizon.
(D) moves counterclockwise around Polaris, and sets below the horizon.

Correct answer: (B)

Using a starwheel for 40° northern latitudes (San Luis Obispo, CA is 35° N latitude) shows Cepheus is a circumpolar constellation, never setting below the horizon, and makes counterclockwise circles around the north celestial pole (near Polaris).

Section 30674
(A) : 7 students
(B) : 34 students
(C) : 0 students
(D) : 0 students
(Blank): 1 student

Success level: 67% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.61

[Version 2]
The constellation Camelopardalis is located at its highest point in the sky, as seen by an observer on February 3 in San Luis Obispo, CA. (Ignore the fact that your starwheel does not include daylight saving time.) Within the next 24 hours, this observer will notice that the constellation Camelopardalis:
(A) moves clockwise around Polaris, and never sets below the horizon.
(B) moves counterclockwise around Polaris, and never sets below the horizon.
(C) moves clockwise around Polaris, and sets below the horizon.
(D) moves counterclockwise around Polaris, and sets below the horizon.

Correct answer: (B)

Using a starwheel for 40° northern latitudes (San Luis Obispo, CA is 35° N latitude) shows Camelopardalis is a circumpolar constellation, never setting below the horizon, and makes counterclockwise circles around the north celestial pole (near Polaris).

Section 30676
(A) : 13 students
(B) : 50 students
(C) : 5 students
(D) : 12 students

Success level: 65% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.59

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