Transparency about the astronomy and tradition behind every number on this site.
Planetary positions are computed with the open-source Skyfield library (MIT licence) driven by JPL DE440s ephemeris data โ the same Jet Propulsion Laboratory development ephemeris used by professional astronomers. Sidereal (Vedic) positions apply the Lahiri ayanamsa; KP calculations use the Krishnamurti ayanamsa. Our independent implementation is validated against published ephemeris references to sub-arcminute accuracy.
Ascendant and house cusps use the requested house system (Placidus for Vedic-style reports, Whole Sign where a tradition calls for it), computed from exact birth time, latitude, longitude and timezone. Nakshatras, padas, dashas and yogas are derived from the sidereal Moon and standard classical rules.
Tithi, nakshatra, yoga, karana, sunrise/sunset, Rahu Kalam, Yamagandam, Gulikai and muhurta windows are computed from local sunrise at the requested city, using its real geographic coordinates and timezone (including daylight-saving changes). Vara (weekday) boundaries follow the local-sunrise rule used in South Indian practice.
Match scores implement the classical koota systems โ the 10-porutham (Tamil/Kerala) and 36-point Ashta-koota (North Indian) schemes โ evaluated from the Moon's nakshatra and rasi of both charts. Scores are literal rule evaluations, not generated text.
Computed positions are real astronomy; the written guidance that accompanies them is traditional astrological interpretation, presented for reflection and cultural interest. For health, legal or financial decisions, please consult a qualified professional โ see our Disclaimer.
If you spot a computation that looks wrong, tell us the date, time and place and we will verify it against the ephemeris โ contact us.