Isolines of Φ = −log ₁₀(L_D(x_O,s_O)/B_⊙) at 0.55 μm during ingress and egress. The Venus solid core plus atmosphere up to 50 km are represented to scale in dashed fill. The atmospheric ring from 50 to 100 km has been resized for a better appreciation of the halo’s structure. The atmosphere above 100 km is not shown. The unrefracted view of the solar disk is shown to scale in yellow in the background. The directions for the Venus North Pole and the Celestial North are indicated. Also indicated is the azimuthal angle φ as defined in Figs. 7–9. In the color code of the figure, blue indicates bright and brown indicates faint. For a color version of the figure, see the electronic journal.