Create Your Davison Chart

A Davison chart (also called a time-space midpoint chart) is a real astronomical chart cast for the exact moment in time and place in space halfway between two births. Unlike a composite chart, which averages planetary positions to produce a virtual chart, a Davison chart represents an actual moment that existed in the sky.

Composite charts midpoint the planetary positions themselves — averaging each person's Sun longitude, Moon longitude, and so on — to produce a virtual chart that never happened in the sky. Davison charts take the opposite approach: they midpoint the moment and the place first, then cast a real natal chart for that synthetic time and location. Same goal (a single chart for the relationship), different methodology.

Synastry overlays two birth charts to show how two people interact — whose Mars touches whose Venus, whose Saturn squares whose Sun. A Davison chart merges them into a single chart that represents the relationship itself. Use synastry to understand the dynamic between you; use Davison to understand the relationship as its own entity.

Calculations use Swiss Ephemeris. The midpoint moment is computed in UTC so timezones combine cleanly, and the geographic midpoint uses spherical geometry — it stays accurate even across the international dateline.

The midpoint date and time are shown in UTC because the two births can come from any pair of timezones. The midpoint location is the great-circle halfway point between the two birthplaces — calculated on the sphere, not as a naive lat/lon average. This is the moment and place we cast the real chart for.

Yes. Generate unlimited Davison charts for free with no signup required. The chart, all aspects, and the underlying calculations are entirely free for everyone.