A student at Princeton is doing his senior thesis on simulated coronagraph data sets, to use as a testing ground for hypothesis testing of somewhat realistic (low SNR) planet signals.
Fomalhaut is the target star for the case study. For its distance of 7.61 pc, 1 AU and 5 AU projected separations correspond to 131.4 mas and 657.0 mas, respectively. For 8-meter telescope observing at 550 nm, = 14.2 mas, so maximum angular separations are 9.27 and 46.33 . Periastron for the inclined, circular 5 AU orbit is .
I handed off a Matlab Fourier propagation model of a concentric ring (spiderweb) coronagraph to my student. This design has a working angle range to frame the system nicely. Also note that 1 AU projected separation at 1.34 pc distance of alpha Cen corresponds to .