Best-fit azimuthally modulated ring model. Panels show a mean image of the best-fit azimuthally modulated ring model described in Sect. 3. Instrument and epochs are displayed on each panel. These mean images were created from the best-fit models of the individual wavelengths per epoch. All panels are plotted with the same colormap and normalized flux scale. The white contours in the images represent the 20, 40, 60, 80 and 95% of the peak’s emission. The white star in the center of the images traces the position of the star in the model.