Interactive Orbital Geometry & Umbral Shadows
Sun Light Umbra Penumbra
Earth Observer View (Sky Simulation) FOV 1.5°
Shadow Cone Ray Cross-Section Umbra / Antumbra
Astronomical Ray Mechanics Reference
Umbra vs. Penumbra

The Umbra is the deepest shadow zone where the Sun's light source is entirely blocked. The Penumbra is the region where only a fraction of the Sun is obscured, creating partial eclipses.

Total vs. Annular (Antumbra)

When the Moon is at perigee (~363,000 km), its angular diameter exceeds the Sun's, allowing the umbra tip to reach Earth (Totality). At apogee (~405,000 km), the Moon appears smaller than the Sun; the umbra ends before Earth, leaving an antumbra that creates a "ring of fire".

Lunar Eclipse ("Blood Moon")

During a Full Moon aligned with a node, the Moon enters Earth's much larger shadow. Earth's atmosphere bends (refracts) reddish wavelengths of sunlight into the umbra, bathing the eclipsed Moon in a coppery red glow.

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