Which of the following features of a telescope determines its light gathering power?
A) The focal length of the objective
B) The focal length of the eyepiece
C) The diameter of the objective
D) Length of the telescope tube
E) None of the above.

Question

Quizplus · Accepted Answer

The diameter of the objective (the main lens or mirror) determines the amount of light that can enter the telescope, and therefore determines the light gathering power. The diameter of the objective determines the light gathering power of a telescope, as a larger objective can gather more light and thus produce a brighter image. The other factors listed may impact other aspects of telescope performance, but not light gathering power.

Which of the Following Features of a Telescope Determines Its