For a diffraction-limited circular aperture, the <Rayleigh criterion> gives $\theta=1.22\lambda/D$. The <photon> <wavelength> is $\lambda=hc/E=1.24\ \mu\mathrm m$, hence \b[$\theta\simeq1.5\times10^{-6}\ \mathrm{rad}$]. This assumes adequate optical quality and sampling; being in space removes atmospheric seeing, not <diffraction>.

Solution

Past exam of the physics A course of the University of Cambridge / 2014 / Paper 2 / Section A / 1 / Solution

 Solution (source code)