Visibility amplitude profiles |V(u, φ)| of the image in Fig. 7. At φ = 90°, the ringing signature is sensitive to the projected diameter d_φ of a hybrid ring composed of the upper half of the n = 1 ring and lower half of the n = 2 ring, as well as to the distance between this hybrid ring and the horizontal line of direct n = 0 emission. These visamps are not exact as they neglect emission from outside the field of view of Fig. 7.