🌕 Lunar Eclipse Simulation: Umbra, Penumbra and the Blood-Moon Colour

Slide the Moon through Earth's umbra and penumbra (impact parameter, Moon distance, contact times P1-P4, magnitudes, totality up to about 107 min) and see why it turns red: a ray-traced model of sunlight refracted through the atmosphere ring, with Rayleigh and ozone filtering, volcanic aerosol and clouds, rendered as a spectrum-to-colour Moon, a coloured shadow plane and an Earth-from-the-Moon view. Unlike the existing lunar-eclipse geometry pages, it computes the Danjon brightness and colour from the atmosphere itself.

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install