Astrology Arith(m)etic

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Interpreting Natal Charts

Interpretation/Charts/Natal/overview.md

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Interpreting Natal Charts

Natal charts reveal the foundational blueprint of a person's life path. Study the placements of planets, aspects, and houses to decode personality themes.

See also: Synastry Overview.

🧭 Construction & Method

Cast for the exact moment and place of birth: convert local clock time to Universal Time (UT = local time − zone offset − DST), compute the Julian Day, local sidereal time (RAMC) and then the Ascendant and Midheaven from latitude, plus planetary longitudes from an ephemeris. A 4-minute error in birth time shifts the Ascendant by roughly 1° (more at high latitudes).

Key factors

📐 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 Natal work the bodies come from the one natal chart.

Approaches

Sources (method)