Our Bith Chart Technicalities

Our birth chart calculations are built upon three core tenets,   the use of equal 30  degree Houses (bhavas), adherence to the foundational principles of the ancient astronomical treatise Surya Siddhanta, and the application of state  of  the  art technology, including the Skyfield astronomical library, the high  precision JPL DE440 ephemeris, and the Hipparcos star catalog.

We blend the profound wisdom of ancient Vedic texts with the most advanced astronomical tools available today. The accuracy of any birth chart the very foundation of a reading depends entirely on the correct calculation of the Ayanamsa, the value that defines the sidereal zodiac. This note explains our meticulous approach to calculating the Ayanamsa and how it provides a more authentic and refined astrological chart.

The True Chitrapaksha Ayanamsa,   A Return to First Principles

Our methodology is rooted in the Chitrapaksha Ayanamsa principle, which is derived from the Surya Siddhanta. This foundational text establishes the sidereal zodiac by fixing the position of the brilliant star Chitra (Spica) at exactly 180 degrees longitude, placing it precisely at the beginning of the sign of Tula (Libra).

Unlike other systems that rely on approximations, we perform a dynamic, real  time calculation for every birth chart. Using modern ephemeris and star data, we determine the exact astronomical position of Spica at the precise moment of birth. The Ayanamsa is then derived directly from this observation, ensuring that the zodiac is anchored to the true, observable position of its fiducial star. This method is known as the True Chitrapaksha Ayanamsa and represents the most literal and astronomically faithful application of the Surya Siddhanta's directive.

How Our Method Differs from the Official Lahiri Ayanamsa

The most widely used Ayanamsa in India is the official Lahiri Ayanamsa, which was established by the Indian Government's Calendar Reform Committee in the 1950s. The committee’s goal was to create a standardized formula for calendrical and religious uniformity in a pre  computer era. The official standard fixed the Ayanamsa having a value of 23° 15' 0" on March 21, 1956. This value was chosen not for its perfect alignment with a historical epoch, but because it was close to the Ayanamsa already in use by most almanac makers at the time, thereby avoiding a drastic and socially disruptive change to the calendar.

Lahiri later specified that his Ayanamsa value needed to be diminished by 5.8 arcseconds to match the value used in the official Indian Astronomical Ephemeris. This famous 5.8" adjustment was a practical calibration for the sake of uniformity, not a move toward greater astronomical purity in the official system. This highlights the tension Lahiri himself navigated between his ideal model and the need for a single national standard.

The Critical Impact on Your Horoscope

This difference, which can be up to an arcminute, may seem small, but in astrology, precision is paramount. If your Ascendant (Lagna) or any planet falls on or near the cusp (the border) between two signs, our more accurate Ayanamsa can result in a different placement than what you might expect from a chart cast with the official Lahiri formula. A shift of even a fraction of a degree can move a planet or the Lagna into an adjacent sign, fundamentally altering the interpretation of the chart and the timing of planetary periods (Dashas). By ensuring the highest degree of astronomical accuracy, we provide a horoscope that reflects the heavens with greater fidelity, offering a more reliable foundation for your astrological journey.