How it is computed

A day runs sunrise to sunrise

The panchang day begins at sunrise, not midnight. The tithi you see at five in the morning belongs to the previous day — that is the tradition, and the commonest "your app shows the wrong tithi" complaint comes from ignoring it.

The sea-level horizon

Sunrise and sunset are computed on the sea-level horizon, as every printed panchang does. Elevation is deliberately ignored: it shifts sunrise by two or three minutes, and with it every Choghadiya, Rahu Kaal and Hora boundary.

Ayanamsa

Sidereal positions use the Indian Astronomical Ephemeris ayanamsa (commonly called Lahiri) in its true form, nutation included. The Sun and Moon come from Meeus's methods (VSOP87, ELP2000); against JPL Horizons over the whole of 2026 the Moon is within 6.5 arc-seconds and the Sun within 0.4, and tithi endings within 6 seconds.

What it is checked against

Festival dates are checked against three panchangs — Drik, AstroSage and Prokerala — and where they disagree with each other we match at least one. The Choghadiya sequence is checked against the printed day and night tables of two of them. Every time cut from sunrise differs from printed sources only by their rounding to the minute.

What is not here

This site currently gives tithi, nakshatra, yoga, karana, Choghadiya and the day's muhurat windows. Kundali, matching and muhurat search are in the app and will come here. There are no predictions anywhere — the app and the site both apply the rules and say what the rules say.

Credits

City coordinates from GeoNames (CC BY 4.0); Hindi names from Wikidata (CC0). Type is Noto Sans Devanagari (SIL Open Font License).