PHYSICS · Subjective · Fermi University Physics · Optics & Photonics · Interference and diffraction · Interference and diffraction
Optics and Photonics, Ch Fraunhofer diffraction from apertures and gratings
Problem
A 150mm telescope objective, used at λ=600nm, is just able to show a double star of separation 1.0′′ as two faint discs touching at the base, using a 150× eyepiece. The observer switches to a 300× eyepiece, expecting the pair to appear more clearly and widely separated as distinct stars, since "more magnification means more resolution". Assess this reasoning quantitatively, including the angle the pair subtends at the eye at each magnification.