On 'Tropical Zodiac in Vedic Astrology'


May 24, 2015 — INDIA (SUN) — Dear Gaurakishor das, Hare Krsna. All glories to Srila Prabhupada. You originally aimed your article, "The Argument for the Tropical Zodiac in Vedic Astrology", at Abhaya Mudra Mataji and her husband, Patita Pavana Prabhu. Since then I have been approached by several devotees to respond to this article, but wanted to give the above named authors or any other person professing to know Vedic astrology ample time to respond. Since they have been unable to respond I will now attempt to do so.

In this response I will focus on the article, "The Argument for the Tropical Zodiac in Vedic Astrology" by Laura Barat that you posted. It should be noted well that my response should not be construed as an attack on the tropical system of astrology. I am simply responding to the statements made by the author. Unlike some persons I have nothing against tropical astrology; it is one out of many systems of divination.

Srila Prabhupada taught us that when we say or write something, especially to a public forum, that we should substantiate it with appropriate pramana. This applies not only when it comes to sastra, but in all areas. Hence, it would seem that you have accepted this article by Laura Barat on face value even though the author did not substantiate even one thing that she wrote. She published this article on her website with absolutely no citations, references or other scholarly apparatus, and we are now somehow expected to believe this.

In the future I may or may not write a formal article with all pramanas, but for this informal article I will use a more relaxed style and may not provide all pramanas, in some places you will just have to accept what I say on faith. I hope you are as gracious with me as you were with her.

Laura writes:

    "In America, Europe and in ancient Greece, Persia and Egypt, the Tropical Zodiac is and was always used."

False. In antiquity, up to the time of Claudius Ptolemy (fl. 150AD), all astrologers in the Greco-Roman world, Egypt and Chaldea like Berossus, Thrasyllus, Balbilus, Dorotheus of Sidon, Antiochus of Athens, Critodemus, Vettius Valens, Nigidius Figulus, Lucius Tarutius Firmanus and Marcus Manilius used the sidereal zodiac.

These ancient Babylonian and Greco-Roman astrologers were well aware that the four cardinal signs (Aries, Cancer, Libra and Capricorn) all began at some distance from the equinoctial and solstitial points. There were, in fact, at least two (ayanamsa) systems in vogue in ancient times called quite simply "System A" and "System B" by historians of astronomy-astrology [1]. These two systems noted that the first point of Aries was either 10 degrees (in System A) or 8 degrees (in System B) from the Vernal Equinox, the position of the Sun on the first day of spring. They were not confused about such things and were well aware of the difference between the two. In fact, in those hoary days the entrance of the Sun into stellar Aries did not coincide with the first day of spring because the Vernal Equinox was to the east of the first point of Aries. And depending on which system was used (A or B) spring began about eight or ten days after the entrance of the sun into the constellation Aries.

It was Ptolemy in his Syntaxis Mathematika and Tetrabiblos who accidently introduced what later came to be known as the "tropical system." At his time what is now known as the tropical zodiac and sidereal zodiac [2] were so close together (less than one degree) as to be indistinguishable by naked eye observations because the ayanamsa was very small almost zero degrees. And, since the sidereal first point of Aries for all practical purposes coincided with the tropical zodiac that Ptolemy's defining the first point of Aries with the vernal equinox became the new standard. And, considering that in those days books were copied by hand on papyrus or later parchment (no printing press what to speak of xerox, PDFs, Kindles or iPads) that only the most popular books were kept in circulation and texts previous to Ptolemy entered into oblivion. It took about 300-400 years before those who used the outdated ayanamsas of +8 degrees and +10 degrees switched over to the zero degree ayanamsa, which continued to be accurate for some time. But because Ptolemy's system was not based on fixed stars ever so slowly his zodiac began to diverge from the stars (sidereal) and it became what is now known as the "Tropical system."

Returning to the Laura's statement:

    "In America, Europe and in ancient Greece, Persia and Egypt, the Tropical Zodiac is and was always used."

As for America and Europe there is currently a school of Western Sidereal Astrologers started in 1944 by the late Cyril Fagan, the father of modern western sidereal astrology. The prominent early followers were the late Donald Bradley/Garth Allen (originator along with Fagan of the Fagan-Bradley ayanamsa), Rupert Gleadow, and Gary Duncan (who I personally knew) among others. Kenneth Bowser is a prominent current member. They use western techniques but on a sidereal zodiac. These western siderealists have their own reasons and point out that western tropical astrology is all wrong and it was a mistake to follow Ptolemy and leave the fixed stars. They want to go back to the original sidereal zodiac used before Ptolemy. The following is an excerpt from Tropical Versus Sidereal Solunars – Part I published in American Astrology, July 1953:

    In ancient time, down to as late as the 5th century A.D., all revolutions [solar returns] were computed in terms of the fixed or sidereal zodiac, which is not affected by precession; whereas in modern times these returns are computed with reference to the tropical zodiac invented in error by Hipparchus about B.C. 139 and which the author [ Claudius Ptolemy] of the Tetrabiblos (2nd century A.D.) strove to popularize. It was the tragedy of the Greek Genius that it could never divest itself of the conviction that the equinoctial points, which perpetually rose and set due east and west respectively were fixed absolutely in space; hence their invention of a series of tropical zodiacs. Had they suspected otherwise they would have discovered that the earth itself was moving. In the Cleostratus version [ of the tropical zodiac] the vernal point is believed to have been fixed in Aries 12°, in that according to Naburiannu (System No. 2) in Aries 10°, in the Callippic or Hellenistic version, according to Kidinnu (System No. 1) in Aries 8°, while Hipparchus fixed it absolutely in Aries 0° (its true position being then Aries 4°51') [ i.e. the sidereal position of the vernal point at the time of Hipparchus, about 130 B.C. ].

[Note it seems that what Neugebauer and Van Hoesen term as "System A" Fagan calls "System 2", that is, Aries 10 degrees; and what Neugebauer and Van Hoesen term as "System B" Fagan calls "System 1", that is, Aries 8 degrees.]

Sidereal system cannot be ignored by Tropicalists

Tropical astrologers are forced to admit the problem of their "moving system" when it comes time to apply a predictive technique such as transits. In transits, called Go-chara in Sanskrit, the relative on-going daily motion of planets in regard to the radical position of the planets at birth is taken into account. Certain transits in particular, such as those of Saturn, must be carefully watched because of their potentially devastating effects. In Vedic astrology, which is sidereal, there is no problem employing this technique. The closer the transiting planet gets to the target the more intense becomes the effect until the planet gets within a critical range, its orb of influence, at which time it unleashes its full effect for good or for bad. The orb of intense influence is usually about one or two degrees.

In tropical astrology transits present a problem for the following reason: suppose the target planet in the birth chart is at 15°Aries in the tropical zodiac. By the time the person whose chart is involved is about 35 years old the accumulated precession of the equinoxes will amount to about half a degree. Which means that 15° of Aries in the tropical zodiac is now half a degree to the west of that point in the sky where the target planet was at the time of birth. This means that the actual position of the target planet is now really at about 15° 30' of Aries in the tropical zodiac. If a tropical astrologer were studying a transit of Saturn to the target planet at 15° of Aries he would make a gross mistake because the target planet has actually moved half a degree because the whole zodiac moved. The older the person is the greater the error because the accumulated precession increases. [3]

To get an accurate result, Tropical astrologers are forced to take into account the precession of the equinox in order to locate the actual position of the target planet. It would of course be much more sensible to use the sidereal zodiac in the first place rather than try to mix apples and oranges.

Another prominent technique in western tropical astrology is the Solar Return chart. In this method a chart is erected for the moment that the transiting sun exactly conjoins the natal sun. The same problem exists in solar return charts as pointed out in transit charts but here the problem is even worse.[4]The whole idea of the solar return chart is to get the exact time of conjunction and then draw up a chart from which predictions are made for the coming year. But because the tropical sun moves away from the true position of the natal sun it will be impossible to get the exact conjunction time unless precession is taken into account. At the present rate of precession this would mean that by the time a person was just eight (8) years old the conjunction time between the tropical sun and the true position would be off by more than two hours, enough time to significantly alter the solar return chart so that the ascendant is totally wrong! This failing of Tropical astrology in regard to transits and solar returns is another demonstration of its internal inconsistency. There is no such inconsistency problem with Vedic sidereal astrology.

Reverting back to Laura, she then says "In about 100 A.D., a Greek astronomer by the name of Hiparchius" this is an apparent error as I know of no astronomer by that name and a quick Google of the name will prove me correct. But there is the famed astronomer by the name of Hipparchus of 2nd century BC whom we mentioned earlier. Among other things it is said that he was the first in the west to notice the precession of the equinox. Ptolemy, continuing the work of Hipparchus came up with a precessional rate of 36"/year, that is 36 seconds of arc per year, whereas the Surya Siddhanta gives a rate of 54"/year. The current measured rate of precession is about 50.25"/year which is very close to the Vedic value but far from the Greek. The Vedic civilization has always known of the precession of the equinoxes as will be explained later.

Laura continues:

    "At the same time the Hindus named their star constellations after the 12 Signs, evidence from several ancient texts shows they lost knowledge of the precession of the equinox and these measurements of 30 degrees each of the star constellations became FIXED and remained so up to the present day. … and the works of the great Varamahira [sic] all mention the Tropical Zodiac as the harbinger of the signs. Oddly, they also mention the first part of Aswini as the beginning of Aries. It becomes clear that the authors were not aware of the Precession of the Equinox … the Indians lost knowledge of precession of the equinox and therefore the Sidereal Zodiac for the Rasis was born."

First of all Laura doesn't present the evidence or even reference these mysterious ancient texts. Further, her statement is simply not true, the works of Varaha Mihira are studied by all serious students of Vedic astrology, he directly states that previously the solstitial point was in a very different place than where it was at his time. He writes:

    "Years ago the dakshinayana was in the middle of Aslesha and uttarayana was in the middle of Dhanistha. This has been mentioned in the early works." Brihat Samhita 4.1

This means that previously Cancer 24 degrees was the northern solstitial point and Capricorn 24 was the southern point. But at the time of Varaha Mihira they were 1 degree Cancer and Capricorn respectively.

The precession of the equinoxes, and thus the tropical system have been known to the Rishis since time immemorial. The Satapatha Brahmana mentions that the vernal equinox took place when the Sun was in the Kritikkas (26AR40 to 10TA00). This and other references in the Brahmana literatures referring to solstitial colures being in various parts of the zodiac prove that the precession of equinoxes was known in remote antiquity (3000 BC). Thus astrologers in India were very well aware of the tropical system of astronomy and precession of the equinoxes.

They also became familiar with tropical astrology because they had to interact with the many Islamic court astrologers such as Al Biruni who came from Arabia, Turkey and Persia and practiced that system. The Muslims dominated the politics of India for 800 years but instead of the Indians taking up tropical astrology, the Muslim astrologers in the courts of the Muslim kings took up sidereal astrology. Why would the victor take up the way of the vanquished? Was it more effective? More accurate?

Laura then says:

    "The Surya Siddhanta is the greatest astronomical text of the Hindus and gives all the calculations to calculate the Lagna, the Nakshatras, planetary positions within Nakshatras and Tropical positions of the planets. NOWHERE in the Surya Siddhanta does it say to use Sidereal Signs and Sidereal positions of planets to erect a horoscope. In fact, there is more evidence in the Surya Siddhanta that the Tropical Zodiac is to be used instead of the Sidereal Zodiac when erecting horoscopes. And here is why….The Surya Siddhanta gives the calculations for finding the Nakshatra position of the planets. It then uses an ayanamsha to convert the planetary positions back to Tropical positions and from there find the Tropical Lagna."

    "After finding the Tropical Lagna the Surya Siddhanta leaves it there. Since it is impossible to find the Sidereal Lagna without the use of the Tropical Zodiac, then it would be concluded that the Surya Siddhanta would mention to convert the Tropical Lagna back to its Sidereal position if that were indeed the method to be used. It does not mention this at all."

In this section the author displays a complete and utter ignorance of the contents of the Surya Siddhanta. We strongly suspect that she is just repeating what some one else told her and so goes the "parampara" of ignorance in the Kali-yuga. And, we note that our own Gaurakishor Dasa is also promoting this "parampara." But before addressing her assertions let us first briefly discuss about traditional Vedic astronomical literature.

Srila Bhaktisiddhanta Saravati Thakura in his purva ashrama as Sriman Bimal Prasada Datta published a translation with commentary on the Surya Siddhanta and Siddhanta Siromani. In his introduction to Siddhanta Siromani he tells us that in mathematical astronomy there are four sub-branches: siddhanta, tantra, karana and sarini. The branch of mathematical astronomy based on observation of planets and stars and their mathematical aspects is called siddhanta. The branch of mathematical astronomy dealing with the hypotheses on siddhanta and its elaborate explanation is called tantra. The branch based on useable mathematics to determine the results of siddhanta is called karana. The tables of calculations (ephemerides) made using the karana texts for calendars, horoscopes etc., are called sarini. An example of a siddhanta text is Surya Siddhanta. An example of a tantra text is Siddhanta Siromani, which is an elaborate and superexcellent commentary by Bhaskaracarya on the Surya Siddhanta. Examples of karana texts are Grahalaghava, and Karana Kutuhala. Examples of sarini are Makaranda and Dinakaumadi , etc.

The Surya Siddhanta is not used for erecting a horoscope or other practical applications. Rather it is a collection of formulas and methods that are available to the astronomer. It is not at all practical for using to calculate anything because for one thing it uses a very long epoch either from the beginning of creation, or beginning of the kalpa or mahayuga. This results in huge unwieldy numbers such as the number of revolutions of the Sun at 4,320,000 of the Moon 57,753,336 of Mars 2,296,832, etc. Dealing with such large numbers would be difficult using a calculator what to speak trying to multiply and divide them by hand.

And Burgess in his introduction to his translation of Surya Siddhanta points out the way that it is written:

    "In the first place, for the terms used there are often many synonyms, which are employed according to exigencies of the verse: thus the Sun has twelve different names, Mars six, the divisions of time two or three each, radius six or eight, and so on. Again the method of expressing numbers, large or small, is by naming the figures which compose them, beginning with the last and going backward; using for each figure not only its proper name, but that of any object associated with the Hindu mind with the number it represents. Thus, the number 1,577,917,828 (SS 1.37) is thus given: Vasu (a class of deities, eight in number) – two – eight –mountain (the seven mythical chains of mountains) – form –figure (the nine digits) – seven – mountain – lunar days (of which there are 15 in a half month).

    "Once more, the style of expression of the treatise is, in general, excessively concise and elliptical, often to a degree that would make its meaning entirely unintelligible without a commentary, the exposition of a native teacher [guru] … This over-conciseness, however is not wholly due to the metrical form of the treatise: it is characteristic of much of Hindu scientific literature, in its various branches; its text-books are wont to be intended as only the text for written comment or oral explication and hint, rather than fully express, the meaning they contain."

As Burgess points out the Surya Siddhanta and other such literature is written in an almost sutra like way where conciseness is valued above clarity. It is humorously said that a sutrakara (writer of sutras) valued conciseness to the point that he would be happier if he were able to somehow subtract a letter or word from his composition rather than have a son born in his family. Hence for brevity's sake a rule is mentioned once and not repeated as the student is expected to know how to apply them under the guidance of a guru. By repeating rules it makes the text longer, just the opposite of the conciseness the author is trying to achieve. It should also be remembered that the Vedic tradition is to memorize a text, I personally know persons who have completely memorized important Jyotish texts. Concise texts without redundant repetitions are shorter hence much easier to memorize.

And, as the Surya Siddhanta itself says:

    "This mystery of the gods is not to be imparted indiscriminately: it is to be made known to the well-tried pupil, who remains a year under instruction." SS 6.24

So without a real guru one will misunderstand the Surya Siddhanta. It also implies that the students be qualified, it is secret and not for everyone. We will now see by direct inspection how a person can misunderstand the Surya Siddhanta because they have no guru.

To be continued in part 2.

Yours in the service of Srila Prabhupada
Shyamasundara Dasa
krsne matirastu


[1] Neugebauer and Van Hoesen, p. 4.

[2] Tropical means the moving or turning system, the tropical zodiac is based on defining the 1st point of Aries as being the position in the sky where the Sun is at when it crosses the equator going from south to north, that is, the vernal equinox, the first day of spring. However, because of various perturbations of the earth's motion the position in the Sun is not in the same place when this phenomenon occurs the next year. This apparent motion of the Sun is called the precession of the equinox. Sidereal zodiac is defined in relationship to the fixed stars in the sky and doesn't move.

[3] Hand, pp. 29-31.

[4] ibid


Burgess, E., 1860, The Surya Siddhanta, A Test-book of Hindu Astronomy, editor Gangooly, P., Delhi: Motilal Banarsidass Publishers Private Limited.

Chakravarty, A.K., 2001, The Suryasiddhanta -- Bibliotheca Indica Series No. 321, Kolkata, India: The Asiatic Society.

Fagan, Cyril, 1971 (first edition), Astrological Origins, St. Paul, Minnesota: Llewellyn Publications

Forrest, Steven, 1984, The Inner Sky: The Dynamic New Astrology For Everyone, New York: Bantam Books.

Hand, R., 1986 (thirteenth printing), Planets In Transit, Glouster, MA: Para Research, Inc.

Madhavan, Dr. S., Modern Astrology, 2012 January, February, Bangalore, India: Agrany Publications.

Neugebauer, O., and Van Hoesen, H.B., 1959, Greek Horoscopes, Philadelphia: The American Philosophical Society.

Siddhanta Sarasvati, Bimal Prasad, 2007, The Surya-Siddhanta and Siddhanta-siromani, editor Danavir Gosvami, Noida, India: Rupanuga Vedic College.


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