Recovery of the scattering screen velocity for a screen that affects a static crescent. Top row: true scattering screen evolves at 50 km/s (center left panel), while the recovered velocity is 51.4 km/s (right panel). Bottom row: true scattering screen evolves at 200 km/s (center left panel), while the recovered velocity is 193.8 km/s (right panel). The slight deviation from the exact velocity arises from numerical errors in the fitting procedure. The left and center right panels show the corresponding reconstructed crescent for each case.