Calculation contract
What is calculated, and what is not
ChartLumen computes supported astronomical chart facts before any optional generated wording. Symbolic meanings are interpretive tradition—not scientific findings—and generated language never becomes a source for placements.
- Ephemeris
- Astronomy Engine 2.x geocentric apparent longitudes
- Coordinates
- geocentric ecliptic-of-date
- Zodiac
- tropical for Western; sidereal for Vedic preview
- Houses
- whole-sign houses from the calculated Ascendant
- Lunar node
- mean lunar node
- Ayanamsa
- Lahiri-aligned quadratic evaluated from Julian centuries; regression checked against Swiss Ephemeris 2.10.03 samples from 1800–2200
- Unknown time
- local noon is used only for date-level planetary estimates; Ascendant, Midheaven, houses, and dashas are omitted
Versioning and limitations
Current calculation version: open-astronomy-v1.1. Western output has focused deterministic regression coverage. Vedic output is a preview with limited reference validation and should not be treated as a complete traditional consultation.
When birth time is unknown, local noon provides only date-level planetary estimates. ChartLumen omits the Ascendant, Midheaven, houses, and dashas rather than implying unsupported precision.
See the validation status or report a reproducible issue through the corrections process.