Why do reflecting telescopes usually have a secondary mirror in addition to a primary mirror?
A) to increase the light-gathering power
B) to make the telescope shorter
C) to increase the magnification
D) to eliminate the focal length
E) to combat chromatic aberration

Question

Quizplus · Accepted Answer

The secondary mirror in a reflecting telescope is used to redirect the light path, allowing the telescope to be more compact and shorter without sacrificing the focal length.

Why Do Reflecting Telescopes Usually Have a Secondary Mirror in Addition