There is ample evidence in Saptarishi Nadi to show that the saptarishis used a tropical zodiac with sidereal nakshatras. Even The Calendar Reform Committee — constituted by the Government of India — confirmed that Surya Siddhanta advocated a tropical zodiac. Above all, the committee favoured a tropical zodiac in its final recommendation. But, before exploring the evidence that saptarishis used a tropical zodiac, let’s go over the basics of the zodiac.

Zodiac signs and the nakshatras – a primer

The 12 signs of the zodiac start with Aries and end with Pisces (30° each; Figure 1).

Zodiac as defined by the sidereal school along with the nakshatras (English and Tamil)
Figure 1. Zodiac as defined by the sidereal school along with the nakshatras (English and Tamil)

But regarding the starting reference point for Aries, two schools of thought exist — tropical and sidereal. The sidereal school says that the tropical zodiac has now moved away from the sidereal zodiac by about 24°. Therefore, to obtain the sidereal zodiac from the tropical zodiac, this difference (ayanamsa) has to subtracted (Figure 2).

Sidereal zodiac = tropical zodiac – ayanamsa

The tropical zodiac has moved away from the sidereal zodiac
Figure 2. The tropical zodiac has moved away from the sidereal zodiac

For example, if the Sun, as per the tropical zodiac, is in Aries, the sidereal school may consider the same Sun to be in Pisces.

Tropical zodiac

The movement of the Sun with respect to the Earth defines the tropical zodiac. Therefore, it has a definite starting reference point; Aries commences when the Sun crosses the march equinox and moves north of the equator (Figure 3). The equinoxes occur twice a year when the day and night are of equal duration. The march equinox is also called as vernal equinox in the northern hemisphere.

March/vernal equinox and the start of Aries as seen in northern hemisphere
Figure 3. March/vernal equinox and the start of Aries as seen in the northern hemisphere

Precession of the equinoxes

This equinoctial reference point — when projected on to the stellar cosmos — coincides with a nakshatra. But this equinoctial reference point keeps on drifting with respect to the nakshatras slowly over the centuries owing to the precession of the equinoxes; this is supposed to occur due to the wobbling of the Earth like a spinning top (Figure 4).

Figure 4. The precession of the equinoxes

In a tropical zodiac, the zodiac signs are not fixed to the nakshatras

In a tropical zodiac, the zodiac signs are not fixed to the nakshatras. As of now, the equinoctial reference point (red arrow in Figure 5) coincides with Uttara Bhadrapada (உத்திரட்டாதி) nakshatra; but this reference point will not coincide with Uttara Bhadrapada nakshatra forever, owing to the precession of the equinoxes.

Nakshatra wheel and the tropical zodiac as on Dec 2018
Figure 5. Uttara Bhadrapada nakshatra coincides with the equinoctial point now

Definition of the zodiac in classical Indian texts

The definitions of the zodiac given by the classical Indian texts like Vedanga Jyotish and Surya Siddhanta are definitely tropical. Vic DiCara has unequivocally explained these definitions succinctly in one of his videos. The definitions start at 3:06 in this video.

Sidereal zodiac

Sidereal zodiac, which is now being followed by the Indian astrologers, uses nakshatras to define the zodiac. For example, the nakshatras Ashvini (அஸ்வினி), Bharani, and the first quarter of Krttika (கிருத்திகை) define Aries (Figure 6). However, each nakshatra (constellations like Ashvini, Bharani, etc.) is composed of a group of stars.

The sidereal zodiac is defined by the nakshatras and Aries starts with Ashvini.
Figure 6. The sidereal zodiac and the nakshatras

Even though the sidereal zodiac starts with Ashvini, there is no definite reference starting point in the starry cosmos. To clarify, the constellation Ashvini has a principal star named β Arietis; but, the exact starting point of the constellation is not marked by any star. However, the treatise Surya Siddhanta (around 400 CE) mentions that the sidereal zodiac ends at the border of Revati nakshatra.

The vexing question of ayanamsa

As the exact starting point of the sidereal zodiac is not defined, various astrologers follow different reference starting points. As a result, we have many sidereal systems following different ayanamsas. For instance, if Jupiter has transited from Aries to Taurus for one sidereal astrologer, it may still be in Aries for another. This confusion regarding the exact value of the ayanamsa is a major unresolved problem in the sidereal school of thought.

The Calendar Reform Committee

The Government of India commissioned The Calendar Reform Committee in 1952. This committee (of which Shri N. C. Lahiri was a member) tried to resolve the vexing issue of ayanamsa.

Surya Siddhanta mentions that the star Spica (Chitra) was close to the starting point of Libra (color coded; Figure 6). As Libra is exactly opposite to Aries, the committee decided that the starting point of Aries to be located 180° from the star Spica. Therefore, this is known as the Chitrapaksha or Lahiri ayanamsa as it anchors the zodiac to the star Chitra (Spica). But this is not accepted by all, and we have many other ayanamsas such as Raman, Krishnamurti, Yukteswar, Fagan Bradley, and Pushya Paksha, which anchor the starting point of the sidereal zodiac at different places. This difference of opinion in defining the sidereal zodiac weakens the credibility of Indian astrology.

How come our ancestors did not even define something as basic as the starting point of the zodiac? However, I don’t think our ancestors erred on this count, but it’s we who messed things up. Let me explain.

Arguments for a tropical zodiac

The nakshatras once started with krttika

The list of the nakshatras did not always start with Ashvini as they do now. For instance, the earliest mention of the nakshatras is found in the Yajurveda; but, the nakshatras listed are 28 in number and they start with Krttika, not Ashvini as listed now. Even in Mahabharata, Krttika is listed as the first nakshatra. However, the precession of the equinoxes can explain this discrepancy (Figure 7).

The march equinox was located close to Krttika at the time of Mahabharata.
Figure 7. Nakshatras at the time of Mahabharata

Maybe, at the time of Mahabharata, the march equinox was located near Krttika and therefore the nakshatras started with krttika.

Later, they started with Ashvini

About 2000 yrs ago, owing to the precession of the equinoxes, the march equinox was located near Ashvini. Therefore, it was then that our ancestors listed Ashvini as the first nakshatra. Most importantly, they must have been aware of the drifting of the stars over the centuries with respect to the tropical zodiac. Even though they used a tropical zodiac, they should have used nakshatras as a reference, for convenience.

Nakshatra wheel as observed today. Ashvini has moved away from the march equinox.
Figure 8. Nakshatra wheel as observed today

The march equinox has shifted now to the Uttara Bhadrapada (உத்திரட்டாதி) nakshatra (about 24° away from Ashvini); as a result, it no longer is appropriate that the zodiac or the nakshatras start with Ashvini. Figure 8 shows the present position of the nakshatra wheel.

Kali yuga is an era of ignorance

The traditional Indian astrologers believe that our shastras and sages recommended a sidereal zodiac. But the earliest classical astrological books available now have all been penned down about 2000 yrs ago, during Kali yuga. In other words, these books were written when the whole of humanity was enveloped in a veil of ignorance. Therefore, as we no longer have access to books written prior to the onset of Kali yuga, it is highly likely that we have lost the wisdom of our sages.

Surya Siddhanta was influenced by Graeco-Chaldean astronomy

The Calendar Reform Committee recognized three periods in the Indian calendar history:

  1. Rig-vedic age culminating in the Yajur-vedic period (till 1300 BC)
  2. Vedanga Jyotisa period (1300 BC ­– 200 AD)
  3. Siddhanta Jyotisa period (400 AD onwards)

With respect to the Siddhanta Jyotisa period, the committee said,

The knowledge of Graeco-Chaldean astronomy was the basis on which the calendar prescribed by the Surya Siddhanta and other Siddhantas were built up. It completely replaced the former Vedanga Jyotisa calendar and by about 400A.D, the Vedanga Jyotisa calendar had completely disappeared from all parts of India.

Report of the Calendar Reform Committee, page 214

It is highly possible that the wisdom of our rishis was lost by the end of Vedanga Jyotisa period or earlier, and it was contaminated with Graeco-Chaldean astronomy. Thus, the knowledge of the precession of the equinoxes was lost in India.

The Calendar Reform Committee favored a tropical zodiac

Surya Siddhanta (S.S) defines the zodiac tropically. The Committee too confirms the same:

The quotations leave not the slightest doubt that according to the compilers of the S.S., the first point of the zodiac is the point of intersection of the ecliptic and the equator, and the signs of the zodiac cover 30° each of the ecliptic.

report of The calendar reform committee, page 240

This is the definition of a tropical zodiac. The report goes on to mention that,

But it is clear from the text that the compilers of the S.S. had no knowledge of the precession of the equinoxes, but they took the first point of Aries to fixed.

Final recommendation of the Calendar Reform Committee insisted further reforms

The Calendar Reform Committee favored a tropical zodiac in its final recommendation:

The calculation of solar (saura) months necessary for determining the lunar months of the same name, will start 23°15′ ahead of the vernal equinoctial point. This tallies with the present practice of most almanac-makers.

This recommendation 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.” (emphasis mine)

report of The calendar reform committee, page 7

Though Indian astrologers are using the sidereal zodiac for long, there is compelling evidence that saptarishis used a tropical zodiac.

Evidence that saptarishis used a tropical zodiac

The traditional Indian astrologers believe that our sages followed a sidereal zodiac. Therefore, they say that the nakshatras are fixed to their respective zodiac signs and cannot be placed anywhere else; for example, Ashvini can only be placed in Aries, Aslesha (ஆயில்யம்) only in Cancer, etc.

On the contrary, if the sages had used a tropical zodiac, they should have described the nakshatras outside their sidereal locations. If we could find any instance of the nakshatras being placed outside their sidereal location, that would be the proof of our sages using a tropical zodiac. Indeed, we find such descriptions in Saptarishi Nadi!

Saptarishi Nadi

Saptarishi Nadi is a collection of books containing discussions of horoscopes by the seven sages (saptarishis) and the consort of Lord Siva, Devi Parvati, herself. It is written in poetic form in the Tamil language. These books were compiled from palm manuscripts found in various parts of Tamilnadu, India, and published by the Government Oriental Manuscripts Library, Madras. Most importantly, they are a treasure house for those who want to analyze the predictions of the horoscopes by the ancient sages. I have discussed at length about this collection in the Saptarishi Nadi section. I have compiled the portions where the saptarishis put forth their arguments in favor of/against some of their predictions in the form of an eBook titled, “Elucidation of astrological predictions by saptarishis: Saptarishi Nadi, Aries ascendant collection.”

Now, we will be examining the evidences in two collections of saptarishi Nadi:

  • Mesha lagna (Aries ascendant) collection. The verses in this collection will be denoted by A, followed by horoscope number and verse. For example, verse 8 in horoscope 47 will be denoted as A – 47.8
  • Kanya lagna (Virgo ascendant) collection

Evidences in the Mesha lagna collection

Evidence 1 – Vishakha 1st padam in Scorpio

Horoscope 47 describes a chart with the Moon in Scorpio.


In verse 26, the sage mentions that the nakshatra is Vishakha (விசாகம்); Vishakha’s 4th padam falls in Scorpio as per the sidereal school of thought. However, the poem says the time remaining in the (vimsottari) dasa at birth is 13 yrs and 8 months of Jupiter dasa; this places the Moon in the 1st padam and not in the 4th of Vishakha. Hence, we see that the sage places Vishakha’s 1st padam in Scorpio! The text is either corrupted or the sage is not using a sidereal zodiac, because the 1st padam of Vishakha simply cannot be in Scorpio in the sidereal zodiac.

Aslesha nakshatra in Leo

Similarly, in verse 8, the sage says the jataki’s husband is born with his Moon in Leo in Aslesha nakshatra (ஆயில்யம்). But, in the sidereal zodiac, Aslesha nakshatra falls in Cancer.

அரியெனும் ராசிஆ யில்யநாளில்
Ariyenum rasi, ayilya nalil
Leo rasi on Aslesha day

This is significant because the sage describes

  1. Vishakha 1st padam in Scorpio and
  2. Aslesha in Leo

and both are placed consistently about 30° beyond their sidereal location. This can happen only if the stars had drifted owing to the precession of the equinoxes (Figure 9). Hence, this proves that our sages used a tropical zodiac!

the nakshatra wheel has drifted about 14 degrees.
Figure 9. Probable nakshatra wheel for Horoscope 47, taking into consideration the precession of the equinoxes

Points to ponder

  1. In the olden days, the days were named according to the nakshatras. The Calendar Reform Committee too mentions this when describing the Vedanga Jyotisa period. It says, “The days were named according to the nakshatras or lunar asterisms in which the moon was found…”. So, when they say Aslesha day, it means the Moon was in that nakshatra.
  2. Some may argue that the phrase “Leo rasi on Aslesha day” may mean that the ascendant was Leo and the nakshatra was Aslesha. On the contrary, in Tamilnadu, when one wants to perform puja (ceremonial offering) to God in a temple, the priest asks for rasi details of the person concerned and the customary reply would be, “Aslesha nakshatra in Cancer rasi”. Therefore, it is natural that the rishis mention the nakshatra and the zodiac sign in which the Moon is found. (Maybe, the rasi is customarily mentioned along with the nakshatra because of the fact that the rasis are not fixed to the nakshatras, though we have forgotten this. Otherwise, mere mentioning of the nakshatra is enough, which would then obviously indicate the sidereal rasi.)

In short,

If Aslesha falls in Leo, then all of Vishaka would also fall in Scorpio (Figure 9); therefore, this confirms that

  • the dasa period indicated is not a mistake, and
  • the rasi mentioned is the location of the nakshatra and not the ascendant.

Taking into account the precession of the equinoxes, the above-mentioned placement of the nakshatras would have occurred about 1000 years ago.

This convincingly proves that our saptarishis used a tropical zodiac!

This horoscope has been translated in full and can be found in this page in the Saptarishi Nadi section.

Evidence 2 – Uttara Bhadrapada in Aquarius

Horoscope 67 describes a chart with the Moon in Aquarius.


One might notice that the ascendant is Cancer and not Aries. Actually, the verse states “மேகமும் சென்மமாக”; மேகம் means water too, and so the ascendant is Cancer. Therefore, we see that this horoscope has wrongly been classified under Aries ascendant.

In verse 48, the sage states that the remaining dasa at birth is 14 years and 10 months of Saturn dasa. Hence, this corresponds to Uttara Bhadrapada (உத்திரட்டாதி) 1st padam, which traditionally falls in Pisces. But the sage has fixed the Moon in Aquarius! We can be absolutely sure that this is not a mistake, because verse 19 confirms that the Sun (owner of Leo) is the lord of the 7th sign from the Moon. Certainly, the sage has positioned Uttara Bhadrapada (உத்திரட்டாதி) in Aquarius!

Evidence 3 – Punarvasu 3rd padam in Cancer

Horoscope 48 describes a chart with the Moon in Cancer.


In verse 34, the remaining dasa at birth is stated to be 7 years and 8 months of Jupiter dasa. As a result, the Moon is in Punarvasu (புனர்பூசம்) 3rd padam, which traditionally falls in Gemini. The sage, however, has already positioned the Moon in Cancer. Certainly, the sage has placed Punarvasu (புனர்பூசம்) 3rd padam in Cancer! This again proves that saptarishis used a tropical zodiac.

Evidence 4 – Mrigashirsha in Capricorn

In A – 29.11, for the following planetary position, the sage describes the birth of the jataka’s father thus:


மாந்தலை நாளேயாகும்மான்ராசி உதிப்பானாகும்
He will be born in Mrigashirsha nakshatra in Capricorn

Mrigashirsha nakshatra falls in Taurus and Gemini, but not in Capricorn. But the sage refers to a birth in Capricorn under this nakshatra! Does this piece of information correlate with other particulars in the horoscope?

For the jataka, his Moon is placed in Libra and the remaining dasa at birth is 2 years, 10 months, and 15 days of Mars dasa. As the nakshatra at birth is not mentioned, the possibilities are Mrigashirsha, Chitra, and Dhanishta (அவிட்டம்). Naturally, Chitra is the obvious choice under the sidereal zodiac and what the siderealists would assume.

The planetary dasa may actually be different

But, if we consider that Mrigashirsha had drifted to Capricorn owing to the precession of the equinoxes, the only possibility is for the jataka’s Moon to be in Dhanishta (அவிட்டம்; Figure 10). As a result, both these particulars correlate each other. This nakshatra alignment would have occurred about 9500 yrs ago!

Probable nakshatra wheel for A – 29. The nakshatra wheel is very different from what is seen today.
Figure 10. Probable nakshatra wheel for A – 29

Then, did the sages explain a horoscope of a person belonging to that period? According to the Hindu way of life, that is not impossible at all. Saptarishis are said to have existed thousands and thousands of years before, and so it is indeed possible for them to have described a horoscope belonging to that period. Sri Ram of the epic Ramayana is said to have existed in the Treta yuga and Sri Krishna in the Dwapara yuga; we are now in the Kali yuga.

Evidence 5 – Satabhishak in Gemini

In A – 37.13, the sage mentions சதயமும் மிதுனராசி (Satabhishak nakshatra in Gemini) when describing the birth of the jataki’s husband.

Probable nakshatra wheel for A – 37
Figure 11. Probable nakshatra wheel for A – 37

In this horoscope, the moon is placed in Sagittarius and the dasa at birth is of Venus. As the nakshatra is not mentioned in the text, the jataki’s Moon must be in Purva phalguni nakshatra (Figure 11).

Other evidences in this collection

Henceforth, only the tropical placement of the nakshatra will be listed as mentioned by the sages, without any explanations.

  1. கோல்ராசி பரணிநாளில் (Bharani nakshatra in Libra), A –58.5
  2. மூலமும் சிம்மராசி (Mula nakshatra in Leo), A –60.5
  3. கன்னி பூரநாள் தோன்றுவானாம் (Purva phalguni nakshatra in Virgo), A –69.12
  4. கடகம் கேட்டை செனிப்பானாம் (Jyeshtha nakshatra in Cancer), A –70.4
  5. கோலது ராசியாகும் கூர்ஓண அவிட்டநாளில் (Shravana/Dhanishta nakshatra in Libra), A –76.11

Update: Mrigashirsha 3rd padam in Taurus

Manuscript evidence for the use of tropical zodiac is available in horoscope 45, which has been presented in a separate post. This evidence is significant, as it is found only in the manuscript and not in the print version of the book.

Evidences in the Kanya lagna collection

  1. செக்குநாள் கன்னிராசி (Satabhishak nakshatra in Virgo), K –18.15
  2. குடம்ராசி பரணிநாளில் (Bharani nakshatra in Aquarius), K –22.5
  3. மங்கலராசி பகர்திரிஓண நாளாம் (Shravana nakshatra in a sign rules by Mars [here, Scorpio]), K– 22.11
  4. தனுசுராசி அவிட்டநாள் (Dhanishta nakshatra in Sagittarius), K –22.29

Here, three instances of the nakshatras being located outside their sidereal location have been mentioned in the same horoscope (K –22), and they all are shifted by about 55°, obviously due to the drifting of the stars (precession of the equinoxes; Figure 12). Even more, this confirms that the zodiac signs mentioned here are the ones in which the Moon was located and not the name of the ascendants.

Probable nakshatra wheel for K – 22
Figure 12. Probable nakshatra wheel for K – 22
  1. மிதுனமும் சதயநாளில் (Sadabhishak nakshatra in Gemini), K –61.5
  2. சோதிநாள் கெண்டைராசி (Svati nakshatra in Pisces), K –62.4
  3. செக்குநாள் கோலாம்ராசி (Satabhishak nakshatra in Libra), K –87.29

This list in not complete for this collection, and further additions will be made as and when I find mentions of tropical placement of the nakshatras.

Is this evidence enough?

This is the evidence found in just two collections of Saptarishi Nadi and that too it’s not complete; there are 10 other collections. Also, a few important points deserve our attention:

The precession of the equinoxes is gradual

A particular nakshatra will coincide with a zodiac sign for about 2000 years and therefore, horoscopes referring to the past 2000 years will appear to follow a sidereal zodiac, when in fact the nakshatras occupy a similar position in the tropical zodiac too.

A planetary dasa is possible with any of the three nakshatras

In some horoscopes, the nakshatra name is missing and only the dasa details are available. The dasa of a particular planet is possible when the Moon is placed in any one of three nakshatras — 9 planets, 27 nakshatras; eg., Mars dasa can occur in Mrigashirsha, Chitra, and Dhanishta. Therefore, we may assume the Moon to be placed in a nakshatra that fits the sidereal zodiac, when, in fact, it is placed in another compatible nakshatra, as seen in horoscope 29, Mesha lagna collection (already discussed). This may be the case in many other horoscopes and one of the reasons those horoscopes have survived without being discarded as explained below.

Kali yuga did play havoc with our recording of history

As those who copied the manuscripts over the past 2000 years were ignorant that our rishis used a tropical zodiac, the tropical mentions of the nakshatras would have made no sense to them; naturally, under the impression that the verses were corrupted, they would have deleted those references altogether, or worse, altered the nakshatras to match their sidereal counterparts or discarded the horoscopes. Indeed, nakshatra and dasa details are missing in some horoscopes, which would have been either by design or chance. Likewise, commentators would also have resorted to a similar sort of editing, unfortunately, under the mistaken notion that they are setting things right.

Taking these points into consideration, it is indeed amazing that we can find at least these many mentions of the tropical placement of the nakshatras. These supposedly few mentions of tropical zodiac by the rishis are more than sufficient for those who can and are willing to realize the truth and accept it when it stares them right in the face: Saptarishis used a tropical zodiac!

Summing it up

Though our saptarishis used a tropical zodiac, this knowledge was lost because of the onset of Kali yuga and various cultural onslaughts. As mentioned by the Calendar Reform Committee, Graeco-Chaldean influence corrupted our Vedic knowledge around 250 BC, and what survived was not the pristine wisdom of our rishis but a hybrid of Graeco-Chaldean-Vedic thought. As a result, sidereal zodiac began to be followed since 400 AD despite the fact that our rishis advocated a tropical zodiac, as revealed in the verses of Saptarishi Nadi. Therefore, it is high time we restored this long-lost aspect of Vedic astrology.