How we compute
Vedic chart mathematics on Daanyam — separate from how seva booking works.
Why DE440 matters
Planetary longitudes drive lagna, rashi, nakshatra, and Vimshottari dasha boundaries. Small errors at birth time compound into wrong dasha lords or house placements. We use the JPL DE440 kernel on our dedicated Astro Engine (Rust, Cloud Run) rather than approximations.
DE440 is the successor to DE431/DE440-family kernels used in professional astronomy; for Jyotish we convert tropical positions to sidereal using Lahiri ayanamsa and apply standard house and dasha rules from classical texts.
Computation pipeline
Birth date, time, and place (latitude, longitude, timezone) → UTC instant → JPL DE440 barycentric/geocentric positions → light-time correction → Lahiri sidereal longitude → whole-sign (or configured) houses → Vimshottari dasha tree.
- Birth time
- DE440
- Light-time
- Lahiri
- Houses
- Dasha
Audit trail (provenance)
Fetched from GET /provenance on the Astro Engine. When live fetch fails, we show the last hourly mirror from our database.
Provenance temporarily unavailable. Cron /api/cron/mirror-engine-provenance will populate a snapshot when the engine is reachable.
How we compare
Sprint 27 will publish side-by-side deltas vs Swiss Ephemeris and sample commercial APIs. Until then, per-request engineUsed telemetry tracks in-house, Astro Engine, and fallback paths.
| Source | Status |
|---|---|
| Astro Engine (DE440) | Production path when USE_ASTRO_API_V2=true |
| Swiss Ephemeris (webapp fallback) | Active until flip soak complete |
| Comparison report | Planned — Sprint 27 |