Jewish CosmologyExplore Jewish time through astronomy.

Equinoxes & solstices

One Sun, four synchronized views of the seasons שמש אחת, ארבעה מבטים מתואמים על העונות

שוויונים והיפוכים

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Spherical geometry

Watch the sides and angles of a spherical triangle change together.

Calculus

Follow the tangent as it moves along a curve.

Interpolation

Compare estimates between known points on a curve.

The observer’s sky

See the Sun and stars cross the dome above Jerusalem.

The sky in 360°

Watch the same sky from a fixed viewpoint as daylight comes and goes.

Rambam’s nine galgalim

See the nested spheres and their shared daily motion around Earth.