Question

A telescope with a 6 m diameter lens is in orbit around Earth.What is its maximum resolution for 400 nm light, i.e. what is thesmallest angle θ(rad) between objects it just can resolve?

Answer 1

θ = 1.22 λ / D describes the resolving power of a circular aperature D

θ = 1.22 * 4.00E-7 m / 6 m = 8.13E-8 rad

(Using Rayleigh's criteria for diffraction)