Ayanansh Explained.

 

Sidereal Vs Tropical Zodiac.

 

In Vedic astrology we define the Zodiac as a natural belt around the ecliptic which traces the apparent movement of the Sun through the constellations or groups of stars. The 12 signs of the Zodiac are derived from the constellations. This is called a Sidereal Zodiac. The position of planets are calculated based on where they are actually observed in the sky, in relationship to the fixed stars (relatively fixed) which form the constellations. This means you can look up in the sky and locate the planets as exactly indicated by the horoscope.

However this is different from the western system that uses the Tropical Zodiac which is based on orientation of the Earth to the Sun and derived from the equinox and solstices. Thus the Sun is assumed to be at zero degrees of Aries at the Spring Equinox. Thus all the other planets are adjusted to a theoretical position based on the observable seasons and do not represent the actual position of the planets in the sky relative to the stars.

This was fine 2,000 years ago when the tropical signs and the constellations were in the same position. However due to a phenomena called the Precession of the Equinoxes which was known in the Vedic age, the tropical signs have drifted away from the constellations.

To explain this: at the Vernal (Spring) Equinox, Sun as seen from Earth is not at the same point against the background of the fixed stars relative to where it was at the same time a year ago. It arrives at the Vernal Equinox point fractionally earlier, making the seasonal year about 20 minutes shorter than the sidereal year.

This is because the earth wobbles like a top as it goes around the Sun due to its slight tilt. The polar axis does not point to the same star over the course of one orbit around the sun, it drifts backwards ever so slightly. As the direction of the wobble around the earth’s axis is in opposition to the Sun, it looks like the vernal point is moving backwards through the 12 signs (tracing an imaginary cone like shape). This called the Precession of Equinox and the process is so slow, that the movement is about one degree per 72 years or it takes almost 2160 years to regress through a whole sign and 25,920 years to trace one cone-like shape.

 

To sum up, the difference is because in the Sidereal system we take the point 180 degrees opposite the star Spica as the starting point of the Zodiac which is the 1st degree of Aries and in a Tropical Zodiac the first point of Aries is taken as the Vernal Equinox, which may not be in Aries against the backdrop of stars.

 

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Ayanansh in Sidereal Astrology.

 

Western astrology mostly uses the tropical zodiac, in which 0° Aries is fixed at the vernal point. The vernal point is the point where the Sun is located at the spring equinox.

By contrast, sidereal astrology uses a sidereal zodiac whose initial point is defined relative to the fixed stars. Sidereal astrology has a western as well as an eastern tradition. The former claims to go back to the Babylonian and Hellenistic traditions, whereas the latter originates from the Indian tradition, which has become known as "Vedic" astrology in recent years. (Since Vedic spirituality does not have anything to do with astrology, this is actually a misnomer, and I shall henceforward call it "Indian astrology" or "sidereal astrology".)

Since the vernal point makes a slow motion relative to the fixed stars, namely the so-called precession of 1° in 71.6 years, the tropical and the sidereal zodiacs slowly drift apart. About 1500 - 2000 years ago, both zodiacs almost perfectly agreed with each other.

However, in our time, the difference between them amounts to 20° and continues increasing.

Nowadays, sidereal ephemerides are derived from tropical ephemerides by subtracting a certain difference value from the tropical positions of the planets. This difference value is called ayanamsha. The Sanskrit term ayanāṃśaḥ is composed of the words ayanam, "course (of the Sun), half-year" and aṃśaḥ, "part", thus literally means "part of the course".

It refers to the distance of a solstice from the initial point of the cardinal zodiac sign that is associated with it. This distance equals the distance of the vernal point from the sidereal Aries point.

 

Sidereal astrologers unfortunately disagree about where exactly in the sky the initial point of the sidereal zodiac should be located.

There are numerous divergent ideas about it and, consequently, a considerable number of different ayanamshas.

New ayanamshas are invented almost every year. Beginners in sidereal astrology are confronted with the difficult problem of deciding which ayanamsha to use, unless they choose to follow the recommendation of their teacher. Hindu astrologers and their western disciples mostly use the so-called Lahiri ayanamsha, whereas the western sidereal tradition mostly uses the Fagan/Bradley Ayanamsha.

 

Lahiri Ayanamsa.

 

This is the ayanamsha mostly used in India, and it is the official ayanamsha used to determine the dates of Hindu religious festivals. It was introduced in 1955 by the Indian Calendar Reform Committee and named after its inventor, the astronomer Nirmala Chandra Lahiri.

Since Indian religious calendars are defined by the ingresses of the Sun into sidereal zodiac signs, Hindu religious celebrations depend on the ayanamsha used in calendar-making. By introducing an official ayanamsha, the Indian government wanted to enforce that religious holidays fell on the same days in the whole country. However, the historical basis of this ayanamsha is problematic and many experts consider it wrong by several degrees.

Lahiri actually intended that the star Spica (in Sanskrit Citrā) should be fixed at 0° Libra. However the official definition of the Lahiri ayanamsha does not realise this idea accurately. This is explained by the fact that the traditional method of calculating ayanamshas does not take into account the proper motion of fixed stars and a small change in orientation of the ecliptic plane.

 

For this reason, some astrologers have proposed an improved version of this ayanamsha, the so-called "True Chitra Paksha Ayanamsha".

 

True Chitra Paksha Ayanamsha.

 

This ayanamsha is considered to be a correction of the Lahiri ayanamsha. The fixed star Spica (in Sanskrit Citrā) is always located exactly at 0° Libra.

 

* Suryasiddhanta Chitra Ayanamsha.

 

The earliest clue that supports the view that Spica/Citra was used as a marker of 0° Libra is found in the ancient Indian astronomy text book  Surya siddhanta.

It must be noted, however, that this work does not talk about ayanamsha, but only mentions the positions of some fixed stars in a sidereal zodiac. In its present form, the Suryasiddhanta was composed near the year 500 CE. Older versions of it are not extant, but are referred to in other texts.

The Suryasiddhanta Chitra Ayanamsha is defined in such a way that the star Spica was at 0° Libra in the year 499 CE if projected on the ecliptic in so-called polar projection. In polar projection, the projection line is not perpendicular to the ecliptic but is drawn through the celestial north pole and the star. Since the above-mentioned Spica-based ayanamshas (Lahiri and True Chitra) are projected on the ecliptic in a right angle, strictly speaking they cannot be justified on the basis of the Suryasiddhanta.

In addition, it must be noted that other star positions given in the Suryasiddhanta are not compatible with Spica at 0° Libra. For this reason, this ayanamsha should not be considered very reliable either.

 

* Krishnamurti Ayanamsha.

 

The ayanamsha used by the astrologer K.S. Krishnamurti (1908-1972) is close to the Lahiri ayanamsha and the True Chitra Ayanamsha.

 

Ayanamshas Fixed at Revatī (zeta Piscium) or the Galactic Centre

 

Ayanamshas oriented towards Revati (ζ Piscium) or the galactic centre are subsumed in one group because the resulting zodiac happens to be almost identical. Since ancient Indian astronomers were not aware of the galactic centre, this coincidence seems to be rather accidental. From a philosophical point of view, it probably makes a lot more sense to fix the sidereal zodiac at the galactic centre than at some random fixed star. Since all visible stars circle around the galactic centre, it could be called the "central star" of our galaxy. The galactic centre is also millions of times heavier than any star.

 

* True Revati Ayanamsha and

* Suryasiddhanta Revati Ayanamsha.

 

According to the Suryasiddhanta, the star Revati (ζ Piscium) was located at 29°50' Pisces. Two different ayanamshas can be derived from this information. With the True Revati Ayanamsha, the star is assumed at this ecliptic position in rectangular projection.

With the Suryasiddhanta Revati Ayanamsha, on the other hand, the zodiac is defined in such a way that Revati had the same position in polar ecliptic projection in the year 499 CE.

 

The latter seems to be more appropriate because the Suryasiddhanta uses polar projection. However, it must be noted that the position of Revati as given in the Suryasiddhanta is incompatible with the positions of Spica and other stars as given in the same work.

Unfortunately, the star positions of the Suryasiddhanta do not allow us to determine the underlying ayanamsha.

 

* Usha & Shashi Ayanamsha.

 

This ayanamsha is named after two authors called Usha and Shashi. It has the star Revati (ζ Piscium) close to 0° Aries (29°50' Pisces)and the galactic centre in the middle of the lunar mansion Mula ("root, origin"), which might have been at the beginning of the nakshatra circle in very ancient times.

The galactic centre is a massive black hole in the centre of the Milky Way. Our Sun and all visible stars circle around it.

 

Raman Ayanamsha and Other Indian Ayanamshas.

 

* B.V. Raman Ayanamsha

 

This ayanamsha was used by the great Indian astrologer Bangalore Venkata Raman (1912-1998). It is based on a statement by the medieval astronomer Bhaskara II (1184-1185), who assumed an ayanamsha of 11° in the year 1183 (according to Information given by Chandra Hari).

Although this ayanamsha is very close to the galactic ayanamsha of Gil Brand, Raman apparently did not think of the possibility to define the zodiac using the galactic centre. According to: Chandra Hari, "Ayanāṃśa", unfortunately without indication of source.

See also: B.V. Raman, Hindu Predictive Astrology, pp. 378-379. Here, the year 389 CE is given as the year of zero ayanamsha.

 

* Shri Yukteshwar Ayanamsha.

 

This ayanamsha is named after Swami Shri Yukteshwar Giri (1855-1936). We have taken over its definition from Graham Dawson. However, the definition given by Yukteshwar himself in the introduction of his work The Holy Science cannot be reconsiled with it. According to his "astronomical reference", the ayanamsha on the spring equinox 1893 was 20°54'36" (1894 according to the revised edition of 1977). At the same time he believed that this was the distance of the spring equinox from the star Revati, which he put at the initial point of Aries. Unfortunately, this is wrong, because on that date Revati was actually 18°23' away from the vernal point. The error is explained from the fact that Yukteshwar used the zero ayanamsha year 499 CE and an inaccurate Suryasiddhantic precession rate of 360°/24'000 years = 54 arcsec/year.

Since Yukteshwar's precession rate is wrong by 4" per year or 6'40" per century, astro.com cannot offer a correct ayanamsha according to Shri Yukteshwar.

Unfortunately, the Yukteshwar ayanamsha, as implemented in the Swiss Ephemeris, does not agree with any information given by Yukteshwar himself. And unfortunately, its ultimate origin is unknown to us.

Although this ayanamsha differs by only a few arc seconds from the galactic ayanamsha of Gil Brand, Yukteshwar obviously did not intend to define the zodiac using the galactic centre. He actually intended a Revati-oriented ayanamsha, but committed the above-mentioned errors in his calculation.

Swami Sri Yukteswar, The Holy Science, 1920 (1949, 1957 and 1977, partly revised), Yogoda Satsanga Society of India.

Also see the paragraphs further above on ayanamshas that are oriented towards the star Revati.

 

* True Pushya Ayanamsha.

 

This ayanamsha was proposed by the Indian astrologer P.V.R. Narasimha Rao, the author of the astrological software Jagannatha Hora. He argues that the human existence has its root in the heart, which corresponds to the sign of Cancer. For this reason he chooses the star Pushya (δ Cancri, Asellus Australis) as the anchor star of the zodiac. According to ancient texts this star is located at 16° Cancer.

P.V.R. Narasimha Rao, "Introducing Pushya-paksha Ayanamsa" (2013).

 

True Mula Ayanamsha (K. Chandra Hari).

 

With this ayanamsha, the star Mula (λ Scorpionis) is assumed at 0° Sagittarius.

The Indian astrologer Chandra Hari is of the opinion that the lunar mansion Mula corresponds to the Muladhara Chakra. He refers to the doctrine of the Kalapurusha which assigns the 12 zodiac signs to parts of the human body. The initial point of Aries is considered to correspond to the crown and Pisces to the feet of the cosmic human being. In addition, Chandra Hari notes that Mula has the advantage to be located near the galactic centre and to have "no proper motion". This ayanamsha is very close to the Fagan/Bradley ayanamsha. Chandra Hari believes it defines the original Babylonian zodiac.

(In reality, however, the star Mula (λ Scorpionis) has a small proper motion, too. As has been stated, the position of the galactic centre was not known to the ancient peoples. However, they were aware of the fact that the Milky Way crossed the ecliptic in this region of the sky.)

 

K. Chandra Hari, "On the Origin of Siderial Zodiac and Astronomy".

 

 

Ayanamshas derived from the Suryasiddhanta and Aryabhata.

 

* Aryabhata Equinox 499 and

* Aryabhata Mean Sun 499

 

The ancient Indian astronomer Aryabhata (476-550) states that from the beginning of the Kaliyuga (Kali Age) in 3102 BCE until the spring equinox 499 CE (Aryabhata's own 23rd year of life) exactly 3600 years have passed. In addition, he assumes the spring equinox at the initial point of Aries.

From this information, two possible ayanamshas can be derived. Either the zero point of the zodiac is assumed at the position of the equinoctial point on the spring equinox 499 CE, or otherwise at the position of the mean Sun exactly 3600 sidereal years after the beginning of the Kaliyuga.

More information on these ayanamshas is found in the General Documentation of the Swiss Ephemeris.

 

* Suryasiddhanta Equinox 499 und

 

* Suryasiddhanta Mean Sun 499

 

These ayanamshas are calculated using the same methods as the two Aryabhata ayanamshas above, however using the year length of the Suryasiddhanta.

 

* Aryabhata 522.

 

According to Govindasvamin (850 n. Chr.), Aryabhata and his disciples taught that the vernal point was at the beginning of sidereal Aries in the year 522 AD (= Shaka 444). This tradition probably goes back to an erroneous interpretation of Aryabhata's above-mentioned statement that he was 23 years old when 3600 had elapsed after the beginning of the Kaliyuga.

D. Pingree, "Precession and Trepidation in Indian Astronomy.

 

Two Ayanamshas for the Zodiac and the Nakshatra Circle?

 

Finally yet importantly, investigations in the "true original" ayanamsha should take into account the fact that the nakshatra circle and the circle of the zodiac were originally created independently of each other. The nakshatra circle was invented by the ancient Indians, whereas the 12-sign zodiac was invented by the Babylonians. Contrary to assertions often made by Hindu astrologers, Pre-Hellenistic Vedic texts do not know or mention any zodiac signs. E.g., the Mahabharata often mentions the position of the Moon or the planets in nakshatras, but never in the zodiac signs or the 12 ecliptic constellations.

In Babylon, on the other hand, there is no mention of a circle of 27 or 28 lunar mansions, whereas the zodiacal constellations and signs are very well-attested. The two systems were brought together and conflated in India in the Hellenistic or post-Hellenistic period. The details of this conflation process are unknown. However, it is rather unlikely that the initial point of the original Babylonian Aries coincided exactly with the initial point of the original nakshatra Ashvini. Instead, the zodiac or the nakshatra circle or both of them could have been adjusted in order to bring them into line with each other and create the conflated circle that is used today. It is therefore possible that the original Babylonian zodiac and the original Indian nakshatra circle had separate ayanamshas. In addition, as has been shown, the nakshatra circle might originally have been defined by the galactic node, which was located at the beginning or in the middle of Mula.

On the other hand, the beginning of the Babylonian zodiac was assumed in Aries, not in Mula/Sagittarius, most probably because the vernal point was located in Aries and the year began in spring. For this reason, the galactic node cannot have played any role in the definition of the Babylonian zodiac. Thus, from a historical point of view, the ayanamshas of the nakshatra circle and the zodiac should actually be investigated separately.

Interestingly, all ancient Indian texts that mention the positions of the solstices and equinoxes relative to zodiac signs place these points at the beginnings of the cardinal signs. The vernal point is always assumed at the beginning of Aries, no text ever places it in Taurus or another zodiac sign, the summer solstice is always at the beginning of Cancer, the winter solstice at the beginning of Capricorn, and the autumn equinox at the beginning of Libra. Since it is unlikely that all those texts were written at the same time, it seems that the zodiac introduced into India was originally tropical, i.e. fixed at the solstices and equinoxes.

Only later, it was transformed into a sidereal zodiac, most probably because Indian astronomers were focused on sidereal observation, but did not know how to handle precession. While some old Vedic texts place the solstices in the nakshatras Dhanishtha and Ashlesha, it is important to note that these texts do not know any zodiac signs yet. Perhaps, the American astrologer Ernst Wilhelm, also an expert in Hindu astrology, comes closest to these facts, since he uses sidereal nakshatras combined with a tropical zodiac.

 

Author: Dieter Koch.