Astronomy quiz question: telescope interferometry

Astronomy 210 Quiz 3, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

Increasing the separation distance between several small diameter telescopes that combine their light would increase their:
(A) light-gathering power.
(B) resolving power.
(C) magnifying power.
(D) (None of the above choices.)

Correct answer: (B)

Resolving power depends on the diameter of the primary of a single telescope, or on the greatest separation distance between several telescopes used as an interferometer (thus acting as "edge fragments" of a much larger telescope). Separating several small telescopes does not affect their collective light-gathering power, nor their magnifying power.

Section 70158
(A) : 15 students
(B) : 28 students
(C) : 3 students
(D) : 1 student

Success level: 64% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.53

Section 70160
(A) : 17 students
(B) : 22 students
(C) : 1 student
(D) : 0 students

Success level: 57% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.52