A Cassegrain telescope has a primary mirror with a 5-m diameter and a hole of diameter 5 cm through the primary mirror. By what percent is the light-gathering power of the mirror reduced because of the hole?
A) 0.01%
B) 1%
C) 20%
D) 50%

Question

Quizplus · Accepted Answer

The area of the hole is much smaller compared to the area of the primary mirror, resulting in a negligible reduction in light-gathering power.

A Cassegrain Telescope Has a Primary Mirror with a 5-M