Sidereal OR Tropical Zodiac for Indian Astrology (Jyotish)? - PART 1

Zodiac is about how we divide the sky to identify position of planets and bodies. Choice of zodiac therefore is the foundation of erecting a horoscope. There are two type of zodiacs that are used - tropical whose starting point changes with time and sidereal which is "fixed" for all practical purposes.

This boils down to one question - where is the starting point of Aries?
If that's not established, a planet can be in different signs for the same date of birth.

As far as Indian Astrology (Jyotish) is concerned, there was hardly any debate or doubt regarding the zodiac to be used. It has however, become a subject of debate in recent years thanks to the impact of social media. As things stand now, Jyotish is overwhelmingly sidereal - except for a very few number of astrologers doing Jyotish who use tropical zodiac to erect vedic charts.

The purpose of this article is to address and resolve the doubt in some people's mind regarding the correct zodiac for Jyotish. I have absolutely nothing against (or for) tropical zodiac but I wish to take a stand when someone claims that tropical is the correct zodiac for vedic chart ie for Jyotish analysis. I also don't have any issues whatsoever if someone is doing Jyotish in tropical. But I have very little appreciation if someone without credible evidence is claiming that everybody doing sidereal is wrong - whether Indian, western or Hellenistic astrology.

If someone is making a claim that BIG, it's only fair to expect that the evidence would not only be conclusively decisive but also commensurate with the volume of intended impact both in quality and quantity. If you want to claim that 99.9% of vedic astrologers around the world have been working with wrong charts since last few centuries, then your evidence better justify that claim. It's only a fair expectation and we will try to understand what evidence has been presented to support that claim.

I am writing this 3 part article that will decisively show that sidereal has always been the correct zodiac for Indian Astrology. In this part 1, I will focus exclusively on references from classical text as Jyotish principles are based on classical text. The scope of this article is references to classical Jyotish text that are available in public domain. Part 2 will talk about astronomy and logical basis while part 3 will show case studies in form of comparative analysis of tropical and sidereal chart of some famous personalities using Indian astrology.

Click here to read Part 2 which is about history, astronomy and logical aspect of the debate.

In the above context, I wish to achieve the following in this article (part 1):

  • examine the evidence presented in form of classical references by the tropical side over last few years (doing Indian astrology)
  • establish that the said evidence is conclusive or irrelevant or ambiguous
  • provide counter evidence to conclusively establish sidereal as the correct zodiac for Jyotish
  • Ideally, only the above should be sufficient to reject tropical zodiac for jyotish because entire Jyotish is based on classics but I will follow up this article with astronomical and factual evidence in next one ie. part 2.

    Let's dive in.

    References provided by tropicalists doing Vedic chart

    Surya Siddhant Chap 14 verse 7-9

    What's claimed (in verse 7)

    The two solstices and two equinoxes are the thread upon which the core of the zodiac exists
    What's the correct translation (and meaning)
    At the centre of the zodiac (bhachakranabhau) there are two solstices and two equinoxes. It makes no statement about where it starts, just mentions a universal fact that's well known.
    What's claimed (in verse 8)
    Two borders are between each point.
    What's the correct translation (and meaning)
    In between them (the above) there are two sankrantis (ingress points) each and the ones that follow them are called vishnupadi (feet of Vishnu).
    What's claimed (verse 9)
    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.
    What's the correct translation (and meaning)
    It's a universal fact, mentioned in many Jyotish texts including Brihat samhita that Sun changes it's ayan or direction towards North and South at these two signs. Doesn't indicate anything about where the zodiac starts and where in the sky these signs are.
    What's claimed (verse 10)
    The twelve divisions beginning from Aries are certainly the months which constitute a year.
    What's the correct translation (and meaning)
    Each ritu (season) takes two signs; from makar sankranti (solar ingress in Capricorn) starts seasons winter onwards. From mesh sankranti (Aries ingress) starts 12 solar months which constitute one solar year. This is by far the only relevant but ambiguous at best verse that vedic tropicalist friends have. All it does is tying up seasons calendar with solar months starting with Aries.

    Reference claimed from Bhagwad Purana

    The so-called references to Bhagwad Purana doesn't even come near the subject matter and I am not sure what's the point of even stating those. Bhagwad Purana khand 5, Chapter 21 verse 3 to 5 merely state that Sun rotates (apparently) at different speeds at solsticial and equinoctial points. Also, Sun goes northwards and southwards toward the two solstices and we can know by observation when it crosses the middle point. It then mentions when shorter and longer days or nights occur depending upon which is solar sign. Thank you, none disagrees. Where does it say the zodiac is reckoned from?

    So that's all for classical evidence to support such an earth shattering claim! That's all for claiming vedas and puranas suggest using tropical zodiac? Shocking but true!

    References to support sidereal zodiac in Indian astrology

    Surya Siddhant

    Vedic tropicalist friends swear by Surya Siddhant. As they are gung-ho about an ambiguous verse (above) in last chapter number 14th of Surya Siddhant (SS) which could also arguably have been added later, I will nevertheless start by establishing the unambiguous and clear references in the same Surya Siddhant right in the 1st chapter.

    प्राणादिः कथितो मूर्तः त्रुटयाद्दोSमूर्तसंज्ञकः । षडभिः प्राणैः विनाणि स्यात्तवषष्टया नाणिका स्मृता ।। नाणि षष्टया तु नाक्षत्रमहोरात्रम प्रकीर्तितम। तत्त्रिंशता भवेन्मासः सावनोSर्कोदयैः स्मृतः ।। ऐन्दवस्तिथिभिः तद्धत्सङक्रान्त्या सौर उच्यते। मासैर्द्धादशभिवर्ष दिव्यं तदह उच्यते ।। SS Chapter 1 verses 11-13

    Surya Siddhant chapter 1 verses 11-13 define the units of time above and below the prana and 6 prana equals one vinadi or pal and 60 vinadi or pal make one nadi or ghati. 60 nadi or ghati constitute one nakshatra ahoratram (stellar day/night cycle). There are more specific details in verses 9 to 13 but but SS is very clear about use of terms in defining units of time measurement.

    The above verse in SS only sets the background to define time in terms of stars but doesn't specify that we measure the position of planets from the stars. That is specified in verses 25 to 28 (below).

    Surya siddhant Chapter 1 verses 25,26,27 define the principles behind speed of planets with respect to nakshatras and exactly define the starting point or measuring one cycle (भगण) of movement of planets. That EXACT STARTING POINT of measuring one round is the end of Revati nakshatra ie beginning of Ashwini nakshatra. It says when a planet moves from the end of Revati nakshatra towards the East and comes back to the same point, it completes one bhagan (भगण) or round of cycle. This is very specific about mapping the locations of planets which is what we do when we erect a horoscope.

    SS Chapter 1 verse 25-27
    पश्र्वाद्वृजन्तोSतिजवान्नक्षत्रैस्सततं ग्रहाः । नीयमानाश्च लम्बते तुल्यमेव स्वमार्गगाः ।। प्राग्गतित्वमतस्तेषां भगणैः प्रत्यहं गतिः। परिणाहवशाभ्दित्राः तद्धशादभानि भुत्र्जते।। शीघ्रगस्स्वर्क्षमल्पेन कालेन महताSल्पगः । तेषां तु परिवर्तेन पौष्णान्ते भगणास्मृतः।।

    Thereafter, SS chapter 1 verse 28 specifies 60 seconds make a minute, 60 minutes make one degree and 30 degree make one sign. It then defines the same bhagan (भगण) as collection of 12 signs (with starting point already established).

    SS chapter 1 verse 28
    विकलानां कला षष्टया तत् षष्ट्या भाग उच्चयते। तत्त्रिंशता भवेद्राशिः भगणो द्धादशैव ते ।।

    Subsequent verses then define the angular distances traveled by each planet in terms number of rounds of THIS circle (zodiac) in one mahayuga. This clearly establishes that planetary position at a point in time is to be measured in stellar terms (not equinoxes and solstices). This is part of basics being written ie. first chapter of Surya Siddhant.

    Brihat Parashar Hora Shastra (BPHS)

    BPHS Chapter 3 verse 4-6

    Look at the conclusive verdict given in sage Parashara's teaching. It says in the sky planets are seen moving eastwards enjoying (passing across) each of the nakshatra. (talking about movement of planets and nakshatras). Zodiac (bhachakra) is divided from Ashwini onward nakshatras corresponding to which 12 divisions are located in the sky Aries onwards known as rashi (sign). Bang on. Everything at one place and the context is clearly capturing movement of all planets. This is called evidence.

    Brihat Jataka (Varahamihira)

    Brihat Jataka chapter 1, Verse 4

    The verse 4 of chapter 1 specifies the body parts of cosmic man (kaalangani) ie head (varaangam), face (aananam) etc to Aries, Taurus etc. It then states the signs starting from Aries at Ashwini (mesashviprathma) with their nine divisions fall at the feet (charan) of stars (navarkshacharanakshatra). This unequivocally settles two questions - where does Aries start from AND do navamsa of signs EXACTLY map to nakshatra pada (charan) in the background. This mapping betweenn navamsa to nakshatra pada is firmly reinforced in verse 7 (below). The verse then goes on to mention kshetra, griha, riksha, bham and bhavan as synonyms of sign.

    Brihat Jataka chapter 1, Verse 7

    This verse mentions the planetary rulerships of various parts in a sign for triamshamsa (D30) for odd and even signs. The second line is where we need to focus. It clearly states the end of Cancer (shashibhavan) etc. is the junction point (sandhi) of asterism.

    If Cancer (and other water signs) have to end at the junction point of star, it's clearly not allowed to have end of these signs (Cancer etc) hanging in the midst of any nakshatra. This is the core of gandanta concept. What's so special about ending of Cancer (and water signs)? It's also the junction point of stars. In tropical method, end of any sign including Cancer can hang around anywhere across the star. The above verse firmly ties the signs to "immovable" nakshatras.

    These verses leave no further room for honest doubt.

    Brihat Samhita of Varahamihira

    Here Varahamihira beautifully compliments what he stated in chapter 1 of Brihat Jataka ie. each navamsa of a sign falls at the nakshatra pada. In Brihat samhita chapter 102, he unequivocally defines the complete structure of each and every sign in terms of specific nakshatras therein. The chapter 102 is all about division of signs and nakshatras in the zodiac. This leaves no room for doubt whatsoever about the fixed relationship of each sign with specific nakshatras.

    Let's dive in.

    Brihat samhita chapter 102, verse 1

    This is as clear as it could get.

    Verse 1 clearly states that all the padas of Ashwini, Bharani and a part of Kritika are in Aries.
    He continues with structure of Taurus sign and specifies that it has remaining part of Kritika, all padas of Rohini and part of Mrigshira nakshatra. Period.

    Brihat samhita chapter 102, verse 2

    Verse 2 states that half of Mrigshira nakshatra (ie. 2 padas), all of Ardra and part of Punarvasu are in Gemini sign. It further states that one remaining pada of Punarvasu, all of Pushya and Ashlesha nakshatras are in Cancer sign. In the same manner, the following verses in chapter 102 continue with all the 12 signs and establish their fixed relationship with specific nakshatras.

    Brihat samhita chapter 102, verse 7

    Verse 7 is the perfect closure for the chapter that simply says Ashwini, Magha and Moola nakshatras start respectively at Aries, Leo and Sagittarius.
    Now where is any logical scope left to think of changing this fixed mapping in the sky?

    Let's move on to another chapter in Brihat Samhita, chapter 3 named Adityacharodhyay (आदित्यचरोध्यायः) that means chapter on Sun's apparent movement.

    Brihat Samhita 3.1/2/3
    आश्लेषार्द्वाद्दक्षिणमुक्तरमयनं रवेर्धनिष्ठाद्यम नूनं कदाचिदासीद्येनोक्तं पूर्वशास्त्रेषु साम्प्रतमयनं सवितुः कर्कटकाद्यं मृगादितश्चान्यत उक्ताभावो विकृतिः प्रत्यक्षपरिक्षणैर्व्यक्तिः वकत्राधिकच्श्रन्दद्रो हीनः पुच्छाच्च याति भगणोदक हीनो वदने पुच्छेSधिकेS राद्याति दक्षिणतः

    It clearly says the journey of Sun's southward (dakshin) ayan is from the middle of Ashlesh nakshatra and that of northward (Uttar) ayan is from the start of Dhanishth nakshatra. That's verse no 1. So it's referencing to zodiac and nakshatras.

    Verse no 2 talks of signs. It says southward ayan starts in Cancer and northward does at Capricorn. Where do you see Ashlesh in sidereal zodiac - Cancer or Leo? Where do you see Dhanishth - in Capricorn or Aquarius/Pisces? Which one is correct? As per sidereal, Ashlesh is in Cancer and Dhanishth is in Capricorn.

    The above verses also say this PATTERN of SUN's RELATIVE MOVEMENT will change with time. This is not saying that nakshatra/sign will change BUT Sun's relative movement will change with times (thereby giving changes in seasonal patterns that we know of today). Remember this chapter name is Adityacharodhyay (movement of Sun). Tropical zodiac is useful to study seasonal changes and related activities. But for human horoscopy?

    Atharva veda

    Atharva veda Kand 10, Sukta 8, Verse 4

    Now this one is straight from Vedas ie Atharva veda Kand 10, sukta 8, verse 4 which says there is a chakra (circle) that has 12 spokes (signs), 3 navels (3 focii including the centre of elliptic) which are held together by 360 nails and their slots. THIS CIRCLE THOUGH SLANTED IS FIXED and IMMOVABLE (avichal). Here the clear emphasis is on immovability of this circle (zodiac) with 12 spokes i.e. demarcation of signs. The 360 locations (degrees) divided in 12 parts are allegorically fixed with 360 nails in the sky.

    Jataka Parijat

    Jataka Parijat chapter 1, Verse 7

    In his popular Astrology classic Jataka Parijat, author Vaidyanatha Dikshit says in chapter 1 verse 7, Aries and other zodiacal signs in the sky consist of nine quarters of nakshatra reckoned from Ashwini are termed as kshetra, riksha, rashi, bhawan and bham. There is clear correspondence between the nine parts of a sign and a nakshatra pada or quarter.

    Hora ratnam and Vashishth samhita

    Jyotish classic Hora Ratnam, believed to have been written by Bal Bhadra around the time Jatak Parijat and Sarvarth Chintamani were written, approximately 800 to 1000 years ago, clearly states in verse 434 that some (people) are suggesting the use of sayan (tropical) longitudes (indicating tropical was new in fashion). It further states that nirayan (sidereal) calculations are being used by all (सकल व्यवहारो), means the majority.

    अत्र केचित सायनार्क वशादेवायन प्रवृत्तिर्दर्शनादयफलम सायनार्क सङकक्रमादेव ज्ञेयमिति वदंति । यतो निरयनगणयनयैव लोके सकल व्यवहारो दृश्यतो।
    (Hora Ratnam verse 434)

    So the argument "tropical was used predominantly at earlier times" doesn't hold water. But the corruption had begun around the time of writing these verse.

    Here's what he quotes from Vasishtha Samhita (of sage Vasishth) as below :

    (तत्र वसिष्ठसंहितायाम)
    सायनत्वे हि ग्रहाः कदाचिदेकनक्षत्रान्तरे नक्षत्रद्वयांतरेणैवोपलभ्यते। एवं सति यात्रादिशुभकार्यमुहुर्तेषु मरणादिदुष्ट नक्षत्राणां गुरुपुष्यादिसिद्धयोगात्र्च व्यवहारो निरयनेनैवोपद्यते । सायनगणना तु नियतविषया। (verse 434 continued)

    If sayan (tropical) calculations are used, sometimes the planets could get in different (obviously wrong) nakshatra owing to the differences in space of nakshatras. For this reason, muhurta for auspicious activities eg. journey etc and rituals related to inauspicious events eg. death are all taken using nirayan (sidereal) and not sayan (tropical).

    Sage Vashishth was one of the 7 sages (saptarishis) and grandfather of sage Parashar.

    This is an import from Sage Vasishtha's Samhita and it SPECIFICALLY talks about tropical versus sidereal in the context of muhurta (electional astrology) or Jataka (human horoscopy).

    He has pointed out a serious technical discrepancy in the accuracy of measuring nakshatras in sayan ie tropical method.

    Now I quote further from Vasishtha Samhita to establish that zodiac is reckoned from nakshatra as below :

    षट् पौष्णभाद् द्वादश रौद्रधिष्ण्यात्सुराधिपाद्वानि नव क्रमेण। पूर्वार्धमध्यापरभागगेंदुङतेSखिलव्योमचरास्तथैव। ग्रहाणां पूर्वार्धमध्यापरभागयोगित्वमुक्तं तन्निरयनगणनयैव प्रत्यक्षतो गणिता गत नक्षञे दृश्यते । Vashishth Samhita verse 435

    See how it lays down the structure of the zodiac in terms of eastern , middle and western portion of the zodiac are counted from nakshatras. Then it clarifies just as moon travels to nakshatras, other planets too move in same manner clearly specifying how to ascertain where is a planet (and its fixed from nakshatras).

    It further says, "from end of Revati nakshatra, 6 nakshatras make the Eastern (beginning) part of the zodiac. Thereafter, 12 nakshatras from end of Ardra, make the middle of the zodiac. And 9 nakshatras from the end of Jyeshtha nakshatra make the western part of the zodiac. So this settles the meat of the debate - where do you count Aries from. That's done from end of Revati nakshatra ie Ashwini nakshatra.


    Conclusion is for the reader to draw. I have called off the bluff that vedas and puranas talk about tropical zodiac. It's in fact the opposite as clearly established by me. Each of the above references in favour of sidereal zodiac is clear, decisive and conclusive. These are overwhelming classical and vedic evidence to support the sidereal zodiac. They all confirm two facts - where Aries is reckoned from ie. from Ashwini nakshatra and the zodiac is immovable. This should leave no further room for doubt in the minds of those who are looking to know the truth. This settles the classical evidence part of the debate.

    Click here to read Part 2 which is about history, astronomy and logical aspect of the debate. Click here to read Part 3 which has practical chart analysis of some famous personalities.

    Sidereal zodiac is the heliocentric power house of Jyotish ecosystem. You can choose to isolate from the universal solar power supply and install personal power generator but why would you do that?

    PS: There was a recent discussion on my Facebook wall on the same topic where both sides have shared their views. I have repeated some of that stuff in this post to make all information accessible at one place. The Facebook post is public so anyone can access it here.

    Author : Partho Banerjee