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2D Lunar Eclipse: Umbra & Penumbra Shadow Geometry

Flat-plane 2D companion to the 3D Lunar Eclipse Simulator: the same orbital geometry and umbra/penumbra circle-overlap maths, with a timeline, ecliptic-latitude and Moon-distance sliders driving a live phase, magnitude and coverage readout.

Space & Astronomy2DModerate60 FPS📱 Mobile-adapted⇄ 3D version

This is the flat-plane companion to the 3D Lunar Eclipse Simulator: the same orbital position maths and umbra/penumbra circle-overlap formulas, drawn as a top-down orbit view plus a shadow-plane cross-section instead of an orbiting 3D scene. Drag the timeline, latitude and distance sliders (or pick a scenario preset) to watch the Moon's disc slide through Earth's umbra and penumbra circles, with phase, magnitude and coverage updating live from the exact same geometry.

⚙ Under the hood

lunar eclipseumbrapenumbrashadow geometryastronomy

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install