1. Fagan-Bradley: This ayanamsa is a construct based primarily on personal research by Cyril Fagan and Donald Bradley. Fagan based his ayanamsa on the historical research that was available in his time. He is credited with the discovery (from the astrological point of view) that the Babylonian zodiac was strictly sidereal. The Fagan-Bradley ayanamsa has been enthusiastically adopted by many western siderealists.
2. Lahiri: This ayanamsa is a contemporary one based on the research of the Indian government’s Calendar Reform Committee. The Committee Report was published in 1955. Lahiri’s ayanamsa comes the closest to a universally accepted value in India and among western Jyotish astrologers.
3. Krishnamurti: This is the personal ayanamsa of K.S. Krishnamurti which he claims to have discovered in very precise work with predictive timing techniques. This ayanamsa has become popular with modern Jyotish astrologers due primarily to dasa timing and placement of planets in divisional (varga) charts. Krishnamurti's books were published in the latter third of the 20th century. The difference between the Lahiri and Krishnamurti zodiacs is very small: 5 minutes 47 seconds.