Geometry from the point of view of an observer at the surface of the planet. The side view demonstrates the geometric relationship between the planet (gray) and the star (orange). The bird’s-eye view demonstrates the shadow (red shading) cast by stellar disk (orange shading) on the horizon plane (gray shading). The red circle is the projected stellar disk, with key intersections marked in the same color as the side-view schematics. Orange circle is the unprojected stellar disk (orange shading in side view) overlaid rotated to the horizontal plane. See the main text for more details.