The crater Tycho on the Moon has an approximate diameter of
MATHEMATICS · Multi-part · ISC · Mathematics · Physics · Physical World and Measurement
Problem
The crater Tycho on the Moon has an approximate diameter of 85km. An observatory wishes to design an optical telescope that can barely resolve this crater as a distinct circular feature when the Moon is at its mean distance of 3.84×108m from Earth.
(i) Assuming observations are carried out with yellow light of wavelength 600nm, determine the minimum diameter of the objective required.
(ii) Suppose instead the astronomers attempt the same observation using radio waves of wavelength 0.21m (the hydrogen line). Keeping the required resolution unchanged, calculate the diameter now demanded of a single–dish radio telescope.
(iii) Comment briefly on the practical implications of your answers to parts (i) and (ii).