Sayana And Nirayana Chakra: Understanding Ayanamsha
By Deborah Allison
This is the second in a series of articles that highlight the unique features and tools of Vedic Astrology when compared to other astrological traditions.
All Vedic astrologers have to deal with the identity crisis that inevitably occurs when clients who are used to Western chart readings, or who simply skim the "Your Horoscope" column in the local newspaper, encounter Jyotish for the first time. Even Jyotish "diehards" may not really understand why there is not alignment between something as basic as the calculation of what sign and degree a planet occupies in these two systems.
The answer lies in the point of reference used for this all- important calculation. Western Astrology relies on what is known as the Tropical Zodiac (Sayana cakra), which uses the Vernal Equinox as the point of reference. The Indian system - Jyotish - uses the Sidereal Zodiac (Nirayana cakra), which adopts a fixed star as the point of reference.
The reason for the discrepancy between these two systems is that there is a "wobble" in the rotation of the earth on its axis. As a result, the Sun does not return exactly to the same point of 0 degrees Aries each spring at the vernal equinox as observed from a fixed star. It misses by a tiny amount (around 50 seconds of arc according to the most widely used reference point). This may not seem to matter much, but when it accumulates over the years, the vernal equinox is seen to slip back and back into the sign of Pisces then eventually Aquarius and so on. This phenomenon is known as precession of the Vernal Equinox.
At the present time, the discrepancy between these two systems is about 23 degrees, 57 minutes. This ever-increasing difference is known as the ayanamsha (moving part). If you subtract the daily specific ayanamsha from the planet's position in a Western tropical chart, you will get its location in the Vedic Sidereal Chart.
A Western Astrologer is going to fix the Vernal Equinox as 0 degrees Aries regardless of whether the Sun is actually observed against the backdrop of the stars in the constellation of Aries on that particular day and year. In fact, eventually, there can be the bizarre situation where the Sun is actually observed by astronomers in the sign of Libra and a Western astrologer says it is in Aries - the opposite sign of the zodiac! This may be a contributing factor to the typical modern astronomer's negative opinions about astrology. However, as all astrology is, at its heart, a divination system, the important thing is how well the astrologer integrates any system with the cognitive faculty of intuition.
Jyotish, in turn, always establishes the planetary position against the backdrop of the fixed stars so that real-time observation matches the chart positions. The Sayana cakra or Tropical Zodiac is used in Jyotish to a limited extend for some aspects of calendar calculations. However, the all-important mapping of the heavens for the purposes of divination strictly uses the positions of the planets against the Fixed or Sidereal Zodiac – the Nirayana cakra.
Since the stars in the constellation of Aries are very dim, the reference star used for "pointing" to the all important beginning of the zodiac of 0 degrees Aries is one of the brightest stars in the heavens. Westerners refer to it as Spica but it is known as Citra in Jyotish. Citra is the marker star for one of the 27 nakshatras that bears the same name. Its brightness is reflected in the symbolism of that nakshatras which is known as "the shining jewel." The ayanamsha based on using Citra as the reference star is known as the Citra Paksha ayanamsha or the Lahiri ayanamsha and is the most widely used in India.
However, if you have had your chart done by several Jyotishis, you may find some minor discrepancies in the positions of your planets. This is due to the fact that there are variant opinions on the ayanamsha, and in some charts, this can result in dramatic displacements either in the main chart or in some of the subtler divisional charts.
(c) copyright 2006 Michael Laughrin
From the August/September 2006 issue of Michael Laughrin's North American Jyotish Newsletter. Click to subscribe to this free Jyotish newsletter.
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