A document describes how to calculate the minimum diameter mirror needed on a telescope to see details as small as 4.95 km on the Moon from Earth. Given the distance to the Moon is 384,000 km and average light wavelength is 565 nm, the calculation using the telescope equation determines the minimum diameter is 5.3 cm.

1. What is the minimum diameter mirror on a telescope that would allow you to see details as small
as 4.95 km on the Moon some 384,000 km away? Assume an average wavelength of 565 nm for
the light received.
Solution
from the equation of telescope
(y/R) = 1.22L/D
y = minimum seperation between two points
R = distance between the moon and earth
L = wavelength
D = diameter of the mirror
(4.95/384000) = 1.22*(565*10^-9/D)
D = 0.053 m
D = 5.3 cm <<----------------answer