Tropical Vedic Astrology

Unbinding the Stars from the Signs


Table of Contents

Key Texts:
»»» Sūrya Siddhānta
»»» Bhāgavata Purāna
»»» Bṛhat Parāśara Hora Śāstra

»»» My Main Videos on this Suject

»»» "Don't Believe the Newbie Foreigners!"

»»» Original Video Transcription (2012)

»»» History of the Zodiac (UAC 2018 Presentation)

»»» FAQ about Tropical Vedic Astrology

»»» Reviews of Other Views

Key Texts

^^^Sūrya Siddhānta

Chapter 14, Text 7:

bhacakra-nābhau viṣuvad dvitiyam samasūtragam
ayana dvitayan caiva catasraḥ prathitāstutāḥ

The two solstices and two equinoxes are the thread upon which the core of the zodiac exists.

Text 8:
tad atareṣu saṅkrānti dvitayam dvitayam punaḥ

Two borders are between each point.

Text 9:
bhānor marakara saṅkrānteḥ ṣaṇmāsā uttarāyaṇam
karkādestu tathavasyāt ṣaṇmāsā dakṣināyaṇam

It takes the Sun six months to reach the northern solstice after entering Capricorn; and six months to reach the southern solstice after entering Cancer.

Text 10
meṣādyo dvādaśaite māsāstair eva vatsaraḥ

The twelve divisions beginning from Aries are certainly the months which constitute a year.


^^^Bhāgavata Purāṇa

Division 5, Chapter 21, Text 3:
sa eṣa udagayana-dakṣiṇāyana-vaiṣuvata-saṁjñābhir māndya-śaighrya-samānābhir gatibhir
The sun moves at varying speed between the northern solstice, southern solstice, and equinotical points.

ārohaṇāvarohaṇa-samāna-sthāneṣu yathā-savanam abhipadyamāno
Its rise towards the northern solstice, its fall towards the southern solstice, and its crossing the middle point can be known by observing time.

makarādiṣu rāśiṣv aho-rātrāṇi dīrgha-hrasva-samānāni vidhatte.
The days and nights grow longer and shorter, revealing which of the signs – Capricorn, etc. – the Sun is in.

Text 4:
yadā meṣa-tulayor vartate tadāho-rātrāṇi samānāni bhavanti
When the Sun is in Aries and Libra, the days and nights are equal.

yadā vṛṣabhādiṣu pañcasu ca rāśiṣu carati
tadāhāny eva vardhante
hrasati ca māsi māsy ekaikā ghaṭikā rātriṣu.
When the Sun is in the five signs starting from Taurus, the days grow longer and nights which grow shorter, month by month.

Text 5:
yadā vṛścikādiṣu pañcasu vartate
tadāho-rātrāṇi viparyayāṇi bhavanti.
When the Sun is in the five signs starting from Scorpio, the days and nights change in the opposite way.

^^^Bṛhat Parāśara Hora

Chapter 3, texts 2-5:

śṛṇu vipra pavakṣyāmi, bha-grahānāṁ paristhitim
Listen, scholar, I will explain the positions of the stars and planets.

ākāśe yāni dṛśyante, jyotir-bimbāny anekaśaḥ
In the sky we see many dots of light.

teṣu nakṣatra-saṁjñāni graha-saṁjñāni kānicit
Some of them are known as “stars” (nakṣatra), others as “planets” (graha).

Rāśī are not mentioned.
They are not "dots of light in the sky" (stars).

tani nakṣatra-nāmāni sthira-sthānāni yāni vai
Those which stay fixed in their places are called “stars”.

gacchanto bhāni gṛhlanti, satataṁ ye tu te grahāḥ
But, those stars which always move, as if they had will and consciousness, are called “planets”.

bha-cakrasya nagāśvy aṁśa, aśvinyādi-samāhvayāḥ
The celestial wheel has integral portions called āśvini and so on. It is like a wheel being turned by a horse.

Nakṣatras are integral portions (aṁśa) of this star-wheel (bha-chakra),
They move together/ as a unit (as “a wheel turned by a horse”)
in relation to something about to be mentioned:

tad dvādaśā-vibhāgas tu, tūlya meṣādi-saṁjñakāḥ
But that same space can also be divided into twelve, known as Aries (meṣa) and so on.

tu ("but") - means rāśī are different from what was described before (nakṣatra).
tūlya ("similar") - means rāśī & nakṣatra are similar, not identitcal.
vibhāga ("differentiated division") - means rāśī are distinct from the star field,
unlike nakṣatra, which are "aṁśa" (integral, inseparable portions) of that star field.

My Main Videos on Tropical and Sidereal Zodiacs^^^



Original Video on the Tropical Vedic Zodiac

June 29, 2012

What the zodiac is. The only difference between sidereal and tropical. The importance or non-importance of which version is correct. The Indian and non-Indian opinions on which version is correct.



Original Q & A

June 5, 2017

Reading the Sanskrit Zodiac definitions and addressing live questions.


Explanation of the Mechanics of Stars and Signs

June 9, 2017

Visual aids explaining the relative motion of nakshatras vs. rashi - with live q&a


Review of Andrew Foss' Opinion

June 27, 2017

Andrew Foss published a very negative opinion about tropical Vedic Astrology, and I replied to it in this video.


Interview on The Astrology Podcast

July 8, 2017

Chris Brennan explores the use of the Tropical Zodiac by having me as a guest on his podcast.


Evolution of the Zodiac

August 11, 2017

The first time I ever presented my understanding of the historical development of the zodiac, how it became associated with sidereal things, and why India stuck with this association.

The War Zone


Refutation 1:
Appeal to Tradition

September 5, 2017

India itself (per Nyaya culture) does accept "tradition" as a good source of evidence. But more important than this, I explore the emotional dynamics involved in arguing against the traditional Indian zodiac system.


Refutation 2:
India's Astrological Stability

September 6, 2017

The continuity of Indian astrological culture is simply do to its compatibility with Indian religion, while the rise of Christianity in the west caused breaks in western astrological culture.


Refutation 3:
You can see Taurus!!!

September 8, 2017

Some argue that the sidereal Zodiac's superior accuracy and realism are verifiable by simple observation. In this video, I dismantle this fallacy.


Refutation 4:
Nakshatra are Part of the Zodiac?

September 11, 2017

I answer the repeatedly asked question, "How can Magha be anywhere but Leo???"


Refutation 5:
It's Just a Calender!

September 13, 2017

I address the claim that stars are "more spiritual" than signs, and that signs are for calendars and calendars have nothing to do with astrology.


Refutation 6:
The Inherently Tropical Zodiac

September 15, 2017

I show how the rulers, elements, and modes of the signs are rational only in relation to tropical factors.


Refutation 7:
Historical Facts

September 20, 2017

I refute historical misconceptions that the original concept of the zodiac was sidereal.


Refutation 8:
Classics of India

September 23, 2017

I show that the classical indian definition of the Zodiac is tropical, and address some mistaken classical references to the sidereal zodiac.


Refutation 9:

September 23, 2017

Closing comments about demonstration of zodiacal superiority and the importance of traditional foundations.



Tropical and Sidereal in Vedic Astrology

May 29, 2018

The content of my presentation at the U.A.C. 2018 conference.


Anniversary Q & A

September 14, 2018

A presentation and live Q&A clarifying the topics, one year after the big "war".



Interview with
Sam Reynolds

February 5, 2019

Some personal information about what caused me to shift from the sidereal zodiac.


Debate with
Richard Fiddler

February 27, 2019

Tropical vs. Sidereal Debate


24 Tropical-Sidereal Dillemas

August 29, 2019

A review of the basics followed by another batch of Q & A



Truly Vedic Definitions

October 7, 2021

Surya Siddhanta, Bhagavata Purana, and Brihat Parashara Hora & the "Foreigners" argument. Live, with Q/A


History of the Zodiac

October 8, 2021

Live Explanation of my History of the Zodiac UAC presentation


What I Said

October 12, 2021

Live explanation of my initial 2012 presentation

^^^"Don't Believe the Newbie Foreigners"

Upon hearing someone say, "The sidereal zodiac is a mistake" the initial reflexive reaction from most users of the sidereal zodiac is, understandably, quite defensive. The largest community of people using sidereal zodiac signs is, of course, the community of Indian ("Vedic") astrologers. Their initial reflex is very often is something to the effect of, "This is our tradition! Who does this foreigner think he is, some newbie claiming to be more important than all our own experts for hundreds of years!?"

Please allow me a moment to address this reaction.

I request you to temporarily forget that I, Vic DiCara, exist at all. Let us instead consider who else besides me has also declared that the zodiac - even the "zodiac of India" - is intrinsically tropical, and not sidereal.

First, we have the Vedas themselves, which used astrology to determine the correct time to perform important and sacred endeavors ("yajña"). Mostly they relied on 27 sidereal nakshatras, but whenever they utilized a 12-fold division, they did so in relation to solstice and equinox (i.e. they utilized only the tropical 12-fold division).

Next, we have the astronomical sections of the Purāṇas, along with the Indian astronomical and astrological classics like Sūrya Siddhānta and Bṛhat Parāśara Hora Śāstra. As shown above, these unequivocally and uniformly define the zodiac as a solstice/equinox phenomenon - i.e. "tropical." (see above for exact quotes)

This being the case, we would expect at least several more contemporary Indian thinkers to question the adoption of the sidereal zodiac. Are there any? Yes, many. I can only mention those I know of.

Classical astrologers such as Varāha Mihira and Aryabhata spoke in favor of a tropical zodiac. Aryabhata did so in the first statement of the fourth chapter of his book, Aryabhatiya. Varāha Mihira did so in Bṛhatsaṁhita (3.1-3) and Pañcasiddhāntikā (3.21 & 32) where he noted that the solstices are the markers for the beginning of Cancer and Capricorn, and these drift through the nakshatras over time, but the tradition developing around him was ignoring this in favor of just keeping things the same.

Of course, we have better records of more recent times...

In the late 19th century, S.B. Dikshita, in his book, History of Indian Astronomy, Part II, concluded that the Indian calendar should be based on tropical zodiac signs, not sidereal – because of the importance of the solstices and equinoxes in Vedic religion. Dikshita recognized the unlikeliness of conservative Indian culture adopting such a radical change and suggested that a partial reform would be to standardize a singular sidereal zodiac on the citrapakṣa ayanāṁśa.

Dikshita’s opinion was echoed exactly by the official Calendar Reform Committee, led by N.C. Lahiri and commissioned by the Indian Government in 1950. The first and second resolution in the committee’s official report was that the start of the year (and thus the zodiac) should be marked by northerly equinox. But they conceded that an ayanamsha can be applied “for religious purposes… as a concession to the prevailing customs.”

Again on page 7 of the report, when elaborating on standardization of the religious calendar, the committee wrote, “This recommendation [citrapakṣa ayanaṁśa] is to be regarded only as a measure of compromise, so that we avoid a violent break with the established custom. But it does not make our present seasons in the various months as they were in the days of Varahamihira or Kalidasa. It is hoped that at not a distant date, further reforms for locating the lunar and solar festivals in the seasons in which they were originally observed will be adopted.”

It is clear that the seven extremely highly-esteemed scientists and scholars commissioned in this committee agreed that the tropical zodiac was correct, but a sidereal zodiac would be required to accommodate the prevailing customs. Thus, they viewed the sidereal zodiac as a compromise with tradition.

In 1930 G.V. Krishnaswami published a paper entitled, Reform of the Indian Calendars, in which he says, “The method of placing the ayanas and the months on a sidereal basis in the Indian calendars is defective and hence there is a difference of about 23 days in the calculations.”

In more modern times, at least three scholars – Krishen Kaul, M.K.A. Patrakam, and T.V. Sivaraman speak very openly against the sidereal zodiac.

Sri Swarupananda Saraswathi Maharaj of Dwaraka Mutt stands behind them, adding that the Dwaraka Mutt has promoted the very same idea for 120 years.

Sri Jayendra Saraswathi Swamigal of Kanchi Mutt also supports them, saying that, “the time has come” for this reform.

Sri Gangadharendra Saraswathi Swamiji of Shri Sonda Swarnavalli Mutt also supports them, saying all must “fall in line with the sayana [tropical] system.”

What can we conclude from all this? Simply: Even if you want to embrace the "Don't Believe the Newbie Foreigners" reaction, you still must deal with the actual facts that indigenous Indian's for dozens of centuries have been trying to challenge the popular sidereal tradition. Thus, the idea that Indian astrology should stop using the sidereal zodiac is, in fact, neither new nor foreign.

My Original 2012 Presentation^^^

What are the twelve signs? They are a way to measure space.

Space is like as a sphere all around us. The Sun and planets move through a narrow band anchored around the middle of that sphere. The twelve signs divide this narrow band into twelve discrete sections.

Why twelve?

The easiest way to explain is to use an analog clock. The clock’s round face represents space, the circular band through which the Sun and planets move. The hour hand represents the Sun.  The minute hand represents the Moon.

Let’s take a clock before it has any hands or markings on its face. Put the hour hand in place and watch it move around the clock’s entire circle. This movement represents the Sun moving through the circle of space (a "year").

Now put on the minute hand. It's movement represents the Moon moving through the entire circle of space (a "month").

Now let’s set both hands to the 12 o’clock position, get out a pen, and let the clock start running. The minute and hour hands both move, but the hour hand moves much slower. Whenever the minute hand comes back to the 12 o’clock position, mark the clock face right where the hour hand is pointing. You’ll wind up with twelve marks.

What you’ve just done is exactly analogous to creating the twelve divisions of the zodiac. Each mark on the clock is the border of a new sign. There are twelve of them because the Moon makes twelve cycles through space in the time it takes the sun to make one. So, each sign contains the amount of space travelled by the Sun during the time it takes the Moon to make one complete circuit.

Take a protractor and measure the distance between each of the twelve marks on your clock. Each one is the same: 30 degrees. That’s why each sign consists of 30° of the complete circle of space.

Sidereal and Tropical Definitions

Sidereal and tropical zodiac systems both follow this definition. The only difference is where they start“marking the clock.”

Tropical signs starts from where path of Sun and planets intersects the celestial equator. This point is called “equinox.”

Sidereal signs start reference to a specific star. There are several different opinions about which star should be used, and how. The most popular is the Lahiri Zodiac, which says the signs begin at a point 180 degrees opposite the star named Spica.

Sidereal signs start from a stellar reference point, but they are not literally the stars themselves, which form thirteen divisions of the circle of space, each one a different size (some twice the size of others). Obviously these constellations are not identical to the sidereal signs, which like the tropical signs, are twelve in number and each one equal in size.

Which One is Correct?

People on either side of the issue tense up over this question, because the perception is that if one defines the zodiac incorrectly then ones astrology, and all of its history and heroes, must be completely bogus. This is a misconception. Using the wrong zodiac does not invalidate an entire astrological system. Many factors are unaffected by how we define the zodiac signs. For example:

  • Aspects by degree are unaffected. In India these are called sphuta-dhṛṣṭi, the aspect system recommended by the Indian authority, Parashara.

  • Planets in Houses are unaffected in the dynamic-house system. In India this system is called bhava-chalit. in India. Planets in whole-sign houses also tend to sturdily resist being affected. This is also true for the houses of subdivisional charts (candra-langa, navāmśa, etc).

  • Fixed Stars: Other systems of measuring space, like fixed stars (called nakṣatra in India), are absolutely unchanged. Techniques based on them are identical for either zodiac definition (e.g. nakṣatra daśā, traditional Indian compatibility, most traditional Indian electional systems, etc.).

  • About 25% of the time, even the signs of the planets and houses will not change.

It’s also very important to note that the further back we go in history towards the early AD centuries, the smaller the difference between tropical and sidereal starting points becomes. Astrologers 1700 years ago, for example, faced no difference at all between the sidereal and tropical definitions.

One definition of the zodiac might be “correct” and the other “incorrect,” but this does not mean that using the wrong one renders your astrological system useless, or discounts its rich history. If we define the zodiac correctly, however, our astrological systems will become clearer and simpler to use. This will only become truer as we move into the future and the discrepancy between the sidereal and tropical starting points continues to increase.

The Indian Opinion

Modern India is a bastion of the sidereal zodiac. Thus it comes as a great shock that India’s own classical literature defines the zodiac tropically! Probably no one is more shocked by this than Indians themselves, who faithfully assumed they had been “following the ancients” by using a sidereal zodiac. Let’s look at a sample of what Indian classical texts actually say.

Sūrya Siddhānta

The most authoritative, fundamental Indian text on astronomical astrology is Sūrya Siddhānta, a title which declares the book to be “Perfect Conclusions of the Sun.” Several early places of the book seem to disfavor sidereal and favor the tropical definition of the signs:

  • 1.13 says that the signs are identical to the tropical months:

A solar month begins when the Sun enters a new zodiac sign. There are twelve months in a year.

  • 1.28 states that the signs are mathematical divisions, not constellations:

60 seconds (vikāla) make a minute. 60 minutes (kāla) make a degree. 30 degrees (bhaga) make a sign. 12 signs (rāśi) complete the circle (bhagaṇa).

  • 3.9-10 gives the principle on which ayanāṁśa is based:  that the stars and signs are different; evidenced by their changing positions in relation to one another: [1]

In one age (yuga) the circle of stars lags behind 600 revolutions towards the east. Use a formula [math omitted for brevity] to find the current location (ayana) of the equinox relative to the stars.

The above references could support the tropical zodiac, but texts 7-10 of the Fourteenth Chapter explicitly and unequivocally put it in black and white:

It is well-known that the circle of signs is split by two diameters. One is the line from equinox to equinox. The other is the line from solstice to solstice. Between each solstice and equinox are two other markers. Each solstice /equinox and the two following markers represent the three strides of Vishnu.

The Sun has entered Capricorn when it begins moving north for six months. It has entered Cancer when it begins moving south for six months. Seasons last for two signs each, beginning from Capricorn with the frozen season. The twelve signs named Aries, etc. are the months which altogether comprise the year.

Here, Sūrya Siddhānta plainly says that solstices and equinoxes define the 12 signs of the zodiac. Capricorn is defined by the Sun beginning to move north at the winter solstice, and that Cancer is defined by the Sun beginning to move south at the summer solstice.

Śrīmad Bhāgavatam

Śrīmad Bhāgavatam is held by most Indians to be penultimate Pūraṇa representing the full maturity of Indian thought. Its fifth division concerns astronomy. Texts 2-6 of the 21st chapter of that division define the twelve zodiac signs, unambiguously, as tropical:

Outer space is measured by relation of heaven and earth. The Sun is the king of all the planets, in the center of everything, keeping everything together. It moves to the north, crosses the equator, and moves to the south. When it goes north of the equator days get longer. When it crosses the equator days and nights are equal. When it goes south of the equator days get shorter. On this basis the Sun moves through the twelve divisions called Capricorn and so forth.

The Sun is at Aries and Libra when the days and nights are equal. Passing through Taurus, etc. the days become longer and then decrease until again equal with the night. Passing through Scorpio, etc. the night becomes longer and then decrease to again become equal with the days.

Thus it is impossible to deny that Śrīmad Bhāgavatam presents a tropical definition of the 12 zodiac signs.

Origin of the Sidereal Zodiac

The stars of sidereal space are a valid and important astrological entity.  India (and almost all cultures) has a valid system of dividing sidereal space with the Moon as the focal point, not the Sun as in tropical space. This system has 27 divisions, not 12, because there are that many sunrises during the time it takes the Moon to complete a full circuit of the heavens.

The idea of 12 sidereal signs comes from wrongly assuming that the correlation between the stars and signs is permanent. In fact, there is no permanent correlation between the two, the signs eternally and very gradually drift backwards through the stars - a phenomena commonly known as "precession of the equinox."

There is a valid need to correlate the signs and stars because their relationship is important for defining very long periods of time (“ages”) and for knowing how and when to keep solar and lunar calendar systems synchronized.

Babylonians measured the correlation of their autumnal equinox with the heliacal rising of stars they called The Scales. Greeks measured the discrepancy of tropical Aries against a stellar counterpart bearing the same name. Ancient and Classical Indians measured the heliacal position of the equinox in reference to their fixed stars.  For example, the Ṛg Veda notes Kṛttikā as the “first” star and the beginning of the celestial circle, because in Ṛg Vedic times, four to five thousand years ago, Kṛttikā heliacally rose with the Vernal Equinox. Later Indian works from nearly two thousand years ago note Aśvinī as the first star, because at that time Aśvinī was the star heliacally rising with the equinox.

Projecting the 12 zodiac divisions into space, based on the then-current position of the vernal equinox, was useful for mathematics and essential for long-term timekeeping, but opened a door for people to think of the signs as stellar entities. It is an easy mistake to make considering that for centuries there was almost no significant difference between the signs and their homonymic sidereal namesakes.

The Western Opinion

Now let’s examine how fundamental western texts define the zodiac.

Mul.Apin of Babylon

Mul.Apin is one of the oldest existing documents of astronomical astrology. It reveals that the ancient Babylonians used a lunisolar calendar of twelve 30-day months per year. They anchored these twelve divisions to the equinoxes and solstices, and created stars to serve as reference points for the occurrence of solstices and equinoxes.

Mul.Apin 1.3.1-12 says:

On the 15th of Tashritu the Scales, the Mad Dog, EN.TE.NA.BAR.HUM and the Dog become visible; 3 minas is a daytime watch, 3 minas is a nighttime watch. [2]

This says that when the days and nights are of equal length (an equinox) the ecliptic star called “The Scales” (Modern-day Libra) rises heliacally (just before the Sun). This occurs on the 15th day of their month named Tashritu (an Autumn month). Similarly, Mul.Apin also says that when the nights are shortest (summer solstice) the ecliptic stars of modern Cancer rise. And when the nights are longest (winter solstice) the ecliptic stars of modern Capricorn rise.

What we see in Mul.Apin is that the solstices and equinoxes are fundamental to the Babylonian’s twelvefold division of space, and that reference stars are used to measure the discrepancy between tropical and sidereal time. The Babylonian’s would insert leap months to re-sync the stars with the equinoxes periodically. This explains why they gave stars the same names as the twelve signs.

One cannot convincingly argue that the Babylonian’s had a sidereal twelvefold zodiac, because the Mul.Apin explicitly describes eighteen sidereal divisions of the ecliptic.

Tetrabiblos of Greece

Ptolemy’s Tetrabiblos is thought of as the “bible” of Western Astrology. 1.10 of that text defines the zodiac with a tropical starting point:

The zodiac is a circle, so there is no clear “beginning” to it. But the sign that begins with the Vernal Equinox, Aries, acts as the beginning.

The next section, 1.11, makes it perfectly clear that the signs are defined in relation to the solstices and equinoxes.

There are two signs at solstices: Cancer is the 30° interval beginning at the Summer Solstice. Capricorn is the same from the Winter Solstice. There are two signs at equinoxes: Aries begins from the Vernal Equinox and Libra from the Autumnal Equinox.

Siderealists suggest that Ptolemy “changed” the Greek system to a tropical one, but I don’t consider this a valid opinion. Ptolemy’s forerunner, Hipparchus, discovered the precession of the equinoxes. Greek authors prior to Hipparchus therefore could not differentiate tropical from sidereal. The first significant post-Hipparchus author, Ptolemy, explicitly states that the “beginning” of beginningless space is judged from the equinoxes and solstices and must follow them, not the stars that temporarily and approximately represent them.


First I explained that the twelve signs are not stars; but are mathematical divisions of space derived from the interplay between the Sun and Moon. So there is no compelling reason to assert that the beginning of the twelve signs should be anchored to a star. It is easier to see the rationale of using the equinox to mark the beginning of the divisions – for this binds the twelve lunisolar polyrhythms firmly to the center of the Earth’s local space.

Siderealists, and Indians in particular, will have a difficult time digesting or accepting this point, because it throws the expertise and validity of their rich astrological history into doubt. “So many great astrologers have been successfully doing it this way in India for so many centuries, how can you say they are wrong?!”

I am sympathetic to this reaction. I went through the same dilemma myself – being of Indian astrological, philosophical and religious background. This is why I felt it important to explain that the zodiac is only one of several fundamental components of astrology, and thus an error in calculating the zodiac does not totally invalidate an astrologer or an astrological system. And I wanted to note that the further back in history we look towards our revered founders, the more insulated they are against the effects of error in this regard, for the discrepancy between the sidereal and tropical measurements grows smaller as we move back towards 300 AD.

But if we indeed value tradition we must never lose sight of its original authorities. Sūrya Siddhānta, Śrīmad Bhāgavatam, Mul.Apin and Tetrabiblos all clearly state that the twelve signs of the zodiac are entirely based on solstices and equinoxes, not stars. If we ignore this, what exactly are we loyal to?

Today the discrepancy between the sidereal and tropical reckoning of the twelve signs is too big to overlook. We cannot postpone taking this issue seriously. Once we admit that stars are not signs, there is no compelling reason to use a star to define the zodiac’s beginning. Beside force of habit, injured pride, the paralysis of shock, or fear of change – is there anything that would stop us all from embracing the unequivocal tropical definitions of the zodiac found in all the ancient and classical literature of the world?

- Vic DiCara

[1] The reason the stars and signs move in relation to one another is not easy to explain. The equinox occurs when the Sun moves into a specific angle to the Earth’s axis and equator. But the Earth’s axis slowly rotates in the same direction as the Earth’s revolution around the Sun. So the axis will align with the Sun for an equinox slightly sooner than the earth actually completes an exact orbit. Gradually the equinox occurs at an earlier and earlier point in the Earth’s orbit, and thus the apparent position of Sun in relation to the stars on that day slowly changes. They very gradually drift backwards through the circle of stars.

[2] According to: Hermann Hunger and David Pingree, "MUL.APIN. An Astronomical Compendium in Cuneiform", p. 43

^^^History of the Zodiac (UAC 2018 Presentation)





The 12 signs of the zodiac is an “eternal” concept. As soon as you have a living being watching the world, trying to figure out when to do what, they easily realize the cycle of roughly 12 full moons within one solar circuit - which is the fundamental basis of the 12 sign zodiac system. But the ability to USE those 12 zones of the Sun's path as part of a skymap did not come until human mathematics and observational tools evolved sufficiently (c.2-3k years ago).

To help the maths evolve, the pioneers of using the zodiac correlated the 12 signs to various observable stars - allowing them to visually fact-check what their calculations proposed. Soon enough, people (like Hipparchus, who is famous for being the first to make a statement about it which we have a record of) noticed that the correlation between the marker stars and the zodiac markers (solstices/equinoxes) wasn’t truly a constant. The stellar markers slowly drifted from the zodiac points they were supposed to mark.

To keep track of this drift, people then came up with what we call “ayanaamsha” in Indian astrology (lit. “solstice segment”).

Most people kept the zodiac anchored to solstice/equinox and used ayanaamsha as a variable to keep their stellar cross-checking accurate, but India wanted to anchor the zodiac to their anchor stars, their indigenous system of lunar constellations: the nakshatras. Thus they created what we call today, “sidereal signs.”

Over the centuries various important people - like Varahamihira, S.B. Diksita, and N.C. Lahiri - have questioned this and hoped for a reform: because this directly subverts the fundamental definition of what the 12 signs were in the first place (divisions of the sun’s path between its solstices and equinoxes). Finally, in the 21st century, we seem to be making some headway on that.


Some FAQ

There are more FAQ Q&A in the Videos I listed above. Here are a few in text format.

Why do you use a tropical zodiac?

Because this is what the classical texts advise. See the top of the page for more information.

Do you find tropical signs more reliable in your practice?

Yes, but this is not important. Every individual has their own ways of doing things and will find different things easier or more difficult at different points in their lives. The real reason to use tropical is beause the founders of the science defined the zodiac that way.

Do the methods given in Jyotisha classics work with tropical signs?

Yes, most of the methods defined in classics work best with tropical signs. In fact some of them cannot work at all without tropical signs. (e.g. ṣaḍbāla, or calculating the ascendant)

Do the classics not say simply what zodiac we should use?

Yes, they do. They clearly say the zodiac is tropical. See the top of this page.

Are there not any old examples of charts indicating what zodiac system they use?

How would one demonstrate conclusively that a horoscope from 1500 or more years ago was sidereal or tropical? (a) the two concepts were still a very few degrees apart, and (b) the margin of error in calculations was at least a few degrees.

Since the classic texts define the zodiac as tropical, why should we suspect that the charts calculated in that era were anything other than tropical? However, marker stars were used to verify tropical calculations, and this gives a semblance of the sidereal concept.

Here is a groundbreaking article written by Madhivanan Panneerselvam (edited by me) that shows Evidence of Traditional Indian use of Tropical Zodiac with Sidereal Nakshatras

How can Asvini not be at the beginning of Aries!?

You find it unusual because you were educated to believe that Aries plays some important role in making Ashvini what it is. However, you recieved a poor education. The original vedic texts about Nakshatras - Rg Veda and Taittiriya Brahmana explain their symbolisms without any reference to zodiac signs. These texts, BTW, begin the nakshatras from Krittika, which many interpret to mean that they aligned Aries with Krittika, not Ashvini.

Four or five thousand years ago, when Rg and Yajur Veda were compiled in their currently extant form, the vernal equinox (the "starting line" for tropical reference) occurred when the Sun was near the stars of Krittika! That is why those old Vedas list Krittika, not Ashvini, as the "first" of the 28 nakshatras. Over time, the Sun's location on the vernal equinox drifts backwards against the circle of stars. About two thousand years ago it had drifted into the stars of Ashvini. That is why later compilations and expansions of Vedic literature list Ashvini as the "first" of the nakshatras. The drifting continues, and today the Sun's position on the vernal equinox is in Uttara Bhadrapada's stellar region.


Written Reviews of Other Views

Early Debate with ISKCON Astrologers

To my knowledge the only people who openly tried to counter my original 2012 Paper were a small group of astrologers from ISKCON ("Hare Krishna"). They attempted to present a Sanskrit sidereal definition of the 12 signs

Comments on P.V.N. Rao:

Comments on David Frawley


  • Sidereal vs. Tropical Debate, by Vaughn Paul Manley,
  • Sidereal vs. Tropical, by Cyber Witchcraft
  • For the Sidereal Zodiac, by Kenneth Bowser

I comment on all three in one post.

Following Tradition