What this Vedic birth chart calculates
This page starts with an astronomical sky calculation at the entered UTC instant, then converts its apparent geocentric tropical longitudes to a sidereal zodiac with an approximate Lahiri ayanamsha. The rashi diagram follows the South Indian fixed-sign layout. The sign containing the sidereal Ascendant is marked Lagna, and Whole Sign houses count from that sign. Seven classical grahas and the mean lunar nodes, Rahu and Ketu, appear in the position table.
If the birth time is known, the Moon’s sidereal longitude also selects one of 27 equal nakshatras and one of four padas within it. If the time is unknown, the page uses a local-noon sample only for the remaining planetary longitudes and withholds Moon, nakshatra, Lagna, and houses. An uncertain historical UTC offset can change the result, especially near a boundary.
The calculation uses Astronomy Engine 2.1.19 and a separately coded Lahiri approximation. It is not a Swiss Ephemeris calculation and cannot claim numerical parity with professional Jyotish software. This tool does not calculate vargas, dashas, yogas, strength scores, or predictive judgements.