You are observing the surface of the Moon with a 1.3 m diameter telescope. Assuming that the telescope resolution is limited only by diffraction effects, what is the diameter of the smallest crater that the telescope can resolve? Assume that the wavelength of light is 574 nm.
Hint: In order to "resolve" the crater as a distinct object, consider that the crater-rims on opposite sides of the crater are two points that can just barely be resolved.
Take the Earth-Moon distance to be 385,000 km.