There are various systems of Ayanamsa that are in use in Hindu astrology (also known as
Vedic astrology) such as the
Raman Ayanamsa and the Krishnamurthy Ayanamsa, Critics of Lahiri Ayanamsa have proposed an ayanamsa called True Chitra Paksha Ayanamsa. The use of ayanamsa to account for the precession of equinoxes is believed to have been defined in
Vedic texts at least 2,500 years before the
Greek astronomer
Hipparchus quantified the precession of equinoxes in 127 B.C. While critical scholars believe these "Vedic texts", at least those centering Spica Cittā (or 0° Libra, Tūla Rāśi), were composed in the common era, between 200 and 400 CE. Lahiri falsely [unsubstantiated claim] intended that Spica be centred in Cittā (0° Tūla, tropical LIB) and exactly 180° from tropical ARI. Spica's ecliptic longitude was approximately 203.2° in the mid 1950s, 203.84° in 2000 and thus its presumed ayanamsa is 23.84° (J2000), 24.2° by 2026, and 25.0° by 2083. The actual longitude of Spica is closer to 29° Virgo than 0° Libra. Thus, the Lahiri ayanamsa is nearly one degree less than the true value of ayanamsa. Centring Spica in Cittā, as Lahiri does, pushes Aldebaran and Regulus off-centre and pushes Antares west and outside its namesake nakshatra. Allowing Spica 45' to 1° east of Cittā's center better aligns Pleiades in Kattikā, centers Aldebaran in Rohini, Regulus in Maghā, and Antares to define the western boundary of Jyestha. ==See also ==