Solar Eclipse Geometry
Interactive simulation — adjust parameters and watch the visualization update in real time.
How it works
A solar eclipse needs the Moon between Earth and the Sun. The umbral cone is where the entire photosphere is blocked; the penumbra is where only part of the Sun is covered. Changing Earth–Moon distance changes whether the umbra reaches the surface (total) or you see a ring (annular).
Key equations
θ ≈ R / d (small-angle)
Umbra / penumbra: tangent lines Sun ↔ Moon, extended toward Earth