Davison Chart Overview
Davison Chart Overview
A Davison chart merges two birth charts by time and location midpoint. It reveals the relationship's shared path.
🧭 Construction & Method
Ronald C. Davison’s relationship chart (1977): a real chart cast for the midpoint in time and the midpoint in space between two births. Arithmetic: JD_mid = (JD_A + JD_B) / 2 (both in UT); φ_mid = (φ_A + φ_B) / 2; L_mid = (L_A + L_B) / 2, taking the shorter way around the globe (some programs use the great-circle midpoint instead). Because it is a real moment, the Davison chart has genuine planetary positions, houses and its own transits and progressions — unlike the composite (midpoint) chart.
Key factors
- Ascendant and chart ruler (the relationship’s “personality”)
- Sun (purpose), Moon (emotional life), Venus (affection) of the relationship
- Angular planets and the 7th/10th houses
- Saturn and nodes (durability and direction)
📐 Arith(m)etic Worksheet
Following the book’s method — “pull three datasets from the catalog” (body, aspect, body) and combine them with sign and house — record each contact as:
| a (body 1) | 1 (sign of a) | house of a | aspect (operator) | b (body 2) | 2 (sign of b) | house of b | orb | applying/separating |
|---|---|---|---|---|---|---|---|---|
| … | … | … | … | … | … | … | … | … |
Then read: (a + 1)^house(a) × (b + 2)^house(b) = interpretation — i.e., body-in-sign, coloured by house, joined by the aspect’s quality. In Davison work the bodies come from the relationship chart.
Approaches
- Technical / Comprehensive
- Emotional
- Spiritual
- Soul-Path
- Step-by-step: Davison Chart Analysis Guidelines
Sources (method)
- Ronald C. Davison, Synastry: Understanding Human Relations Through Astrology (1977) — the Davison relationship chart (midpoint in time and space)
- Mikah Smith, Astrology Arith(m)etic — The Building Blocks of Astrology (Schizo Studios EPUB, 2025-12-31), vault copy: Astrology Arith(m)etic - Book Text