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Zodiac symbols on the terrace of a Gopuram.[1]

A word used in ephemerides which indicates how many degrees, minutes and seconds of arc separate the tropical zodiac from the sidereal zodiac. Western astrology usually works with the tropical zodiac in which the signs of the zodiac are not identical to the stellar constellations. Therefore the values given in ephemerides used in the West are based on the tropical zodiac. In order to calculate the position of a planet in the sidereal zodiac one needs to subtract the Ayanamsha number given.

Owing to the precession of the equinoxes, the tropical zodiac moves a further degree away from the sidereal zodiac every 72 years.

It is by no means easy to calculate this Ayanashma value accurately and with any certainty. Whereas the beginning of the tropical zodiac is exactly defined by the position of the vernal equinox, which equates to 0 degrees of Aries, this is not so easy with the sidereal zodiac. Consequently several different Ayanashma values have been estimated, which may differ by several degrees.

In the New International Ephemeris 1900 – 2050 (published in France in 1993 by Editions St. Michel) the Ayanashma number given for the first day of January 2000 is 23 degrees, 51 minutes and 11 seconds. This number was calculated by N.C. Lahiri and is recognised by the Indian government. Indian astrology works with the sidereal zodiac, which has led some Indian astrologers to spend much time trying to find a solution to this problem. The other recognised Ayanashma figures are close to this officially recognised number.

Most important Ayanamsas

Name Date Value 0°-Ayanamsa[2]
Lahiri January 1, 1900 22°27’37.7” September 2, 285 06:42 UT
Lahiri January 1, 2000 23°51'11"
Fagan/ Bradley January 1, 1950 24°02’31.36” December 12, 221 22:48:587091 UT
Krishnamurti August 20, 292 12:47:58 UT
Aldebaran August 16, 220 06:59:25 UT


The different systems explained by Dieter Koch (2016).

Notes and References

  1. At Kanipakam, Andhra Pradesh/ India.
  2. Values from: Northanger's Journal: Ayanamsa, 2010