Which of these is a reason for using mirrors rather than lenses in telescopes?
A) Lenses are more expensive to make than mirrors.
B) Most transparent materials focus light of different colors to different spots.
C) Lenses can only be supported by their edges, making them sag in the middle (mirrors can be supported from behind).
D) All of these choices are correct.

Question

Quizplus · Accepted Answer

Mirrors are preferred in telescopes because they avoid chromatic aberration (B), can be supported from behind to prevent sagging (C), and are generally less expensive to produce in large sizes compared to lenses (A).

Which of These Is a Reason for Using Mirrors Rather