How we calculate
Different Jyotish software can give slightly different results because of different conventions. Here is exactly what we use, so you can compare with confidence.
| Planetary positions | Apparent geocentric positions from the open-source astronomy-engine library (VSOP87 / NOVAS-derived models), accurate to about an arcminute — far finer than any astrological boundary needs in practice. |
|---|---|
| Zodiac | Sidereal, Lahiri (Chitrapaksha) ayanamsha, 23°51′25.5″ at J2000 (mean), with nutation applied — the same definition used by Swiss Ephemeris and most Indian software. |
| Lunar nodes | Mean node for Rahu; Ketu exactly opposite. |
| Ascendant | Calculated from apparent sidereal time, true obliquity and geographic latitude/longitude. |
| Houses | Whole-sign houses from the Lagna. |
| Navamsa | Standard Parashari D9 (each sign divided into nine parts of 3°20′). |
| Vimshottari Dasha | Starts from the Moon’s nakshatra; year of 365.25 days. |
| Sade Sati | Saturn’s sidereal sign ingresses relative to the natal Moon sign, refined to within one hour. |
| Time zones | Historical IANA time-zone rules (including daylight saving and war time) for the birth place and date, via your browser. You can override the UTC offset manually. |
| Place search | About 70,000 cities and towns with their coordinates and time zones from GeoNames (CC BY 4.0), bundled with the site so searches never leave your browser. |
| Divisional charts | All sixteen Parashari vargas (D1–D60) by the BPHS rules, including the unequal D30 and the movable/fixed/dual D45. A planet within a few arcminutes of a division boundary can fall differently in software that rounds the division width. |
| Strength | Shadbala and Bhavabala by BPHS (Saptavargaja with five-fold friendship, Sripati bhava madhya); Ashtakvarga and Prastharashtakvarga by the standard bindu tables (Sarvashtakvarga total 337). |
| Other dasha systems | Yogini dasha in exact 365.25-day years; Jaimini Char dasha by K.N. Rao’s rules; Chara karakas by the seven-karaka scheme. |
| KP system | Placidus cusps with the KP (new) ayanamsha, 249-sub Vimshottari divisions with sub-sub lords, and four-level significators. |
| Varshaphal | Exact sidereal solar return, Muntha, a documented Panchadhikari year-lord rule, and the Mudda (annual Vimshottari) dasha. |
| Ayanamsha display | We use the true Lahiri value (including nutation). Some software prints the mean value, which differs by up to about 17″ — enough to move a planet by a few seconds of arc, never enough to change a sign. |
Verification
We test our calculations against published reference dates. For example, they reproduce Saturn's sidereal ingresses into Capricorn (24 January 2020), Aquarius (17 January 2023) and Pisces (29 March 2025), Jupiter's ingress into Taurus (1 May 2024) and Rahu's into Pisces (30 October 2023). Ascendants are cross-checked against an independent horizon calculation.
Interpretation
Interpretive text on this site describes traditional beliefs from classical Jyotish sources. It is not a prediction of events and is not professional advice.