Lecture
This lecture addresses the ability of an astronaut in orbit around Earth to distinguish houses on the surface 250 km below, by calculating the minimum angular size a human eye can perceive and the angular size of a house at that distance. Using the Rayleigh criterion, the lecture explains the resolution power of optical systems and applies it to determine that a human can resolve objects of about 10^-4 radians, which matches the angular size of a house at that distance.