Astrology Engine

Explore the calculations behind a chart of the sky.

Astrology Engine calculates planetary positions, chart angles and house cusps. Follow a birth chart from its first inputs, or look inside the engine to understand the calculations that make it possible.

Two paths into the engine

Start here

How to Build a Natal Chart

Learn how birth details become a chart of the sky. Follow the geometry, try the calculations, and assemble a natal chart in your browser.

Begin the chart journey

Go deeper

Inside Astrology Engine

The astronomy, mathematics, and software behind chart calculation. Explore the source data and numerical methods that carry a position in space into a calculation you understand.

Explore the engine

Explore the library source, README and architecture on GitHub.