Three ZIMPOL PSFs (top), model fittings (middle), residuals (bottom). Left: minimal r₀ of the sample. Middle: median r₀. Right: maximal r₀. The main differences are due to some static aberrations not taken into account in our model (only the pupil and its central obstruction are taken into account). The hyperbolic arcsine of the intensity is shown to enhance details. The same intensity scale is used per column (data, model, residuals), but differs between columns.