The angular diameters of the Moon and Sun vary slightly because the orbits of the Moon and Earth are slightly elliptical.

Question

Quizplus · Accepted Answer

The angular diameters of the Moon and Sun vary because their distances from Earth change due to the elliptical nature of the Moon's orbit around Earth and Earth's orbit around the Sun. When either is closer, its angular diameter appears larger, and when farther away, its angular diameter appears smaller.

The Angular Diameters of the Moon and Sun Vary Slightly