Wheel of Time – Astronomy in Vedanga Jyothisha

What is Jyothisha ((ज्योतिष)? What is Vedanga Jyothisha?

The primary purpose of Jyothisha throughout the Indian history is to keep time.  It is evident from the continued use of Panchang (almanac) in India. So why was it important for our ancestors to keep time to such minute detail and why are we still following those techniques? (btw, details of the techniques/calculations have evolved over time as needed). What are the books or the sources of the knowledge of those techniques of time keeping in India?

Before we go into the details of the importance of time and the ways in which it is followed and kept track as part of Jyothisha, let’s first see what is Jyothisha.

What is the first image that comes to your mind when you hear ‘Jyothisha?” or “Jyothish?”

  1. An astrologer sitting in a TV studio explaining how your day is going to be based on your rasi?  A horoscope chart? Dreaded Sade-Sati?

  2. Or the following

  3. Does the following Image (celestial sphere) ever come to your mind when you think of Jyothisha?

Image courtesy: By Tfr000 (talk) 20:06, 29 March 2012 (UTC) (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)%5D, via Wikimedia Commons

  1. Do the following terms come to your mind when you hear the word Jyothisha?

  2. Ghati? Vighati? Lipta? Yuga?

  3. Do you think of the following metrics when you hear the word Jyothisha?

  4. Truti ( 0.031 µs) or 1,728,000 human years?

Most probably the first set of images come to our mind immediately. Whereas we may rarely or never associate the second set of images/terms/units with Jyothisha.

But, do you know that the roots/origins of Jyothisha in India are in the second set, not the first set? The first set is called “Phalit Jyothisha”, i.e. predictive astrology, whereas the second set is the timekeeping part, i.e. the Astronomical and Mathematical Sciences of India which are studied as part of Vedanga Jyothisha. They predate predictive astrology.

BTW, the image in the second set is known as the celestial sphere. I’ll explain that when I explain Zodiacal belt in my later articles.

So what does Joythisha mean and why is it called Vedanga Jyothisha?

Jyothisha comes from ‘Jyothi” meaning “light”, and “Isha” meaning, ‘formless, nameless, genderless, eternal truth”. So it’s the ‘light of isha”.

Vedanga: Veda means knowledge. Anga means limbs. Vedanga means ‘limb of Vedas’.

There are 6 vendagas.

Reference: https://en.wikipedia.org/wiki/Vedanga

  1. Shiksha (śikṣā): phonetics, phonology, pronunciation.[1]

  2. Chandas (chandas): prosody.[5]

  3. Vyakarana (vyākaraṇa): grammar and linguistic analysis

  4. Nirukta (nirukta): etymology, explanation of words,

  5. Kalpa (kalpa): ritual instructions

  6. Jyotisha (jyotiṣa): Auspicious time for rituals, and astronomy

Since Jyothisha is a Vedanga, it’s called Vedanga Jyothisha. Vedanga jyothisha is known as the ‘Eye of the Vedas” as it throws light onto that that cannot be otherwise seen.

Jyothisha throws light onto time; past, present and future.

There are 3 parts to Jyothish: Ganita (that pats that keeps track of the grahas and calculates their motion), Muhurta (determine the auspicious time for important events in life and Jataka (predictive astrology including life’s purpose and realizing the divinity within)

Timekeeping is very important for Indians for mundane purposes like a) tracking the seasons, eclipses etc.,  for b) ritual purposes to time the festivals and events (muhurta) and for c) astrology.

This is the reason I prefer to use the term Jyothisha as opposed to astrology because astrology is just but one part of Jyothisha.

So timekeeping and understanding time is the essence of Jyothisha. It does so by studying ‘Jyothis” (luminous bodies) in the sky. I.e. via Astronomy. And to study astronomy, we need math. Hence Jyothisha is that science in India as part of which Astronomy (Khagola Sastram) and Mathematics (Ganitha Sastram) are studied.

Did you know?

GRA means ‘that which grabs”. This is the root word for “gravity”, “grasp” etc. When it’s used in Ganita (i.e. astronomy) part of Jothisha as opposed to Jataka part, it still means the same thing, i.e. that body in the space that grabs the other bodies. And hence by exerting this physical influence on each other, these grahas are kept in their orbits . So the word ‘graha’ when used in the context of Ganita (i.e. astronomy side) part of Jyothisha, it refers to any body that grabs. Hence Sun is a graha as per Jyothisha. So the word ‘PLANET is a wrong translation of the word GRAHA even from the astronomy side of Jyothisha, not just from the philosophy perspective (karma siddhanta).

I don’t know vs. I don’t believe

It is unfortunate that it is NOT common knowledge in current India that Jyothisha’s primary purpose is timekeeping, and astronomy was developed as a response to this purpose.

Instead,  “Phalita Jyothisha”, the later development that is popularized by the TV culture at the expense of the Ganita (i.e. math and astronomy),  dominates the discussions on Jyothisha. It does not mean that Phalita Jyothisha is not valid or is not useful. It is valid and it has its uses. But we cannot understand the evolution of Jyothisha without understanding the timekeeping side of this science.

We sometimes believe in things without knowing what they’re about. I don’t know how many of us actually understand what is quantum physics. But we automatically think that it must be valid because it has the word physics in it. And we tend to throw Jyothisha, of which Hindu astronomical knowledge and Hindu mathematics are a big part of, out of the window.

Back to Timekeeping in Jyothisha

Sources of knowledge for time keeping in India primarily include: Surya Siddhanta, Drik Siddhanta, Manu Samhita, Vishnu Purana, Aryabhata etc.

Surya Siddhanta is believed to have originated around 1500 BCE in India (probably even older) and thought to have been written down in a formal way in 6th-7th century CE during the golden age of Guptas. Surya Siddhanta contains Trigonometry origins. From Wikipedia: The Surya Siddhanta contains the roots of modern trigonometry. Its trigonometric functions jyā and koti-jyā (reflecting the chords of Hipparchus) are the direct source (via Arabic transmission) of the terms sine and cosine.

Aryabhata’s works, that were most likely based on Surya Siddhanta and other similar knowledge bases, which expanded these ancient thoughts and formalized even further were later translated to Arabic during the golden age of Islam. Islamic authors gave due credit to Indian astronomers when they translated these works into Arabic and Persian. But when those books reached Europe, Europeans started calling them Arabic works, not referencing the source, but referencing the messenger.

However, Islamic scientists did add their contributions to Astronomy by inventing some very useful mechanical devices for measurements like compass, which were later brought to India as well. It’s the amalgamation of the knowledge and instruments between Indian and Islamic scholars during the medieval times, that formed the basis for later day astronomical developments. Ofcourse, in the ancient times, there was transmission of knowledge between India and Greece regarding Astronomy.

The relationship between Time and Space

What is that we need to measure time? How can we define time?

It’s space that we need to measure time. Time changes. To measure change, we need reference points and space provides that reference points (Ref: Dic ViCara, a vedic Jyotishi).

Think of the wall clock. We’re able to tell time-based on the movement of hands on the clock. Movement of the hands wrt to what? Wrt a stationary white/black background.

Planets move and by measuring the distance that they move wrt relatively stationary objects like stars, our ancestors were able to measure time. When our ancestors looked at the sky and when they saw that the moon moved by a certain distance (actually by a certain degree within 360 degrees zodiac) wrt to stationery stars (Yes. Stars themselves are not stationary, but for the observational purposes they appear stationary wrt earth), our ancestors were able to say this is the ghati of this day and this is the day of this month etc.

Recall this image.

Image courtesy: By Tfr000 (talk) 20:06, 29 March 2012 (UTC) (Own work) 

During the night time, if you’re standing on earth and you look up, will you not be able to say that the moon moved by a certain angle wrt to the stars behind it? Will you also not realize that the horizon looks like a semi-circle?

Similarly, during daytime, if you observe the sun or the shadow of an object that traces sun, will you not be able to tell that Sun has moved wrt a stationary object on earth by a certain degree?

And if you observe for a few days, will you not realize that the phenomenon is cyclical? That is, the same thing happens again and again between two sunrises and between seasons?

Recall this image below.


How by observing the relative motion of the sun and moon wrt earth, we can understand the formation of eclipses and find clues to timing the eclipses.

Over a few months and a few years, if a group of us observe and share our notes, we’ll get a good idea that there is a cyclical phenomenon with a certain regularity and you can actually plan your activities around the motion of the celestial objects. That’s called Time or Kala in Sanskrit. Kala (काला) means ‘Consciousness Time’.

Hence Time and Space, although are distinct, are inseparable. They are two sides of the same coin. Two ways of describing the same phenomenon.  Hence Astronomy and Calendar are inseparable and hence Panchang is describing an Astronomical Phenomenon. Therefore Trigonometry and Gravity were described in Surya Siddhanta and by Aryabhata etc. much before Newton or Copernicus because, ancient civilizations like India’s obsession with timekeeping.

Did you know? Lokamanya Balagangadhar Tilak wrote a book on ‘Vedanga Jyothisha’ and that book is available in public domain in the US?

Hindu Units of Measurement of Time

Primary reference: http://veda.wikidot.com/vedic-time-system

Another reference: https://en.wikipedia.org/wiki/Hindu_units_of_time

“Kalo gatinivrtti sthiti: samdadhati” (Sankhayana Aranyaka 7.20).

From wikipedia: Hindu measurement of time in Logarithmic scale image is reproduced below. (Image author:  Ilmari Karonen )


Note the following.

Time measurement goes from 10^-7 to 10^22 (^ should be read as to the power of), i.e. micro to macro.

Here’s the comparison with SI scale.

From micro level of, (Sidereal metrics)UnitDefinitionRelation to SI unitsTrutiत्रुतिBase unit≈ 0.031 µsRenuरेणु60 Truti≈ 1.86 µsLavaलव60 Renu≈ 0.11 msLīkṣakaलीक्षक60 Lava≈ 6.696 msLiptaलिप्ता60 Leekshaka≈ 0.401 sVipalaविपलPalaपल60 Lipta≈ 24.1056 sVighaṭiविघटिVinādīविनाडीGhaṭiघटि60 Vighaṭi≈ 24 minNādīनाडीDandaदण्डMuhūrtaमुहूर्त2 Ghaṭi≈ 48 minNakṣatra Ahorātram (Sidereal Day)नक्षत्र अहोरात्रम्60 Ghaṭī≈ 24 h30 Muhūrta≈ 24 h

To the macro level of

The Four Yugas[hide]4 charaṇas (1,728,000 solar years)Satya Yuga3 charaṇas (1,296,000 solar years)Treta Yuga2 charaṇas (864,000 solar years)Dvapara Yuga1 charaṇas (432,000 solar years)Kali YugaSource: [1]

Earth inside a celestial sphere

Img Courtesy: By Prithwis (Own work) [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)%5D, via Wikimedia Commons

The cycle repeats itself, so altogether there are 1,000 cycles of Mahā-Yuga in one day of Brahma.

  1. One cycle of the above four Yugas is one Mahā-Yuga (4.32 million solar years)

  2. A Manvantara consists of 71 Mahā-Yuga (306,720,000 solar years). Each Manvantara is ruled by a Manu.[9]

  3. After each Manvantara follows one Saṃdhi Kāla of the same duration as a Kṛta Yuga (1,728,000 = 4 Charaṇas). (It is said that during a SaṃdhiKāla, the entire earth is submerged in water.)[9]

  4. A Kalpa consists of a period of 4.32 Billion solar years followed by 14 Manvataras and Saṃdhi Kalas.[9]

Food for thought: For mundane purposes, Ghati and Vighati should be sufficient. For festivals and seasons tracking purposes, samvatsara is sufficient. Then why do you think Indians went out of way to one extreme, i.e.  Truti, i.e.  0.031 µs , a micro unit of time to the other extreme, i.e. Kalpa,  a period of 4.32 Billion years?

That kind of micro numbers on one side, and the macro numbers on the other side can serve only one purpose, i.e. the scientific purpose, not mundane alone.

And how do you think they measured such micro and macro times? Did they secretly keep an atomic clock in Geneva to measure micro-units? Of Course not. They made these measurements available to everyone by defining them in a practical way.

As per Vedic astronomy: 1 unit of prāņa is the time an average healthy man needs to complete one respiration or to pronounce ten long syllables called guravakşara.

The time taken to tear apart the softest petals of a lotus is called ‘TRUTI’

100 Trutis make 1 Lub and 30 Lub make 1 Nimesh, and so on.

Cyclical Nature of Time

From the above metrics, you may have noticed something, i.e. time repeats itself.

Sunset follows the previous sunrise, that follows another sunset etc. Pournami (Full moon) follows Amavasya (New moon) and after the same time period, Amavasya is followed by Pournami etc.

Yuga also repeats themselves after some time.

Hence overall, time repeats itself from micro to macro level.

Hene in Hindu Astronomy and hence in Jyothisha, time, i.e. kala is referred to as Kalachakram,  कालचक्रम, కాలచక్రం (Wheel of Time).

Not ‘kala rekha’ (Not Timeline, but Wheel of Time). By observing the astronomical phenomenon, ancient Indians realized that time is cyclical (and hence space is spherical)(celestial sphere).

Hence the earth is called ‘Bhoo Golam” (భూగోళం). Bhoo refers to earth and Golam means a round object. They knew that the earth is spherical, as time is cyclical and time and space are related.

Interesting tidbit: One of the techniques used for muhurta in Jyothisha is based on a system called ‘Hora Sastra”. This hora system is another way of measuring time. This system was developed by the famous Hindu astronomer Varahamihira (who lived during the golden age of Guptas). The word Hora is arrived at by deleting the leading letter ‘a’ and the trailing ‘tra’ from ‘ahoratra’ (अहोरात्र) ( అ హోరా త్ర). As per the Hora system, a day (from sunrise to sunrise) is divided into 24 horas. Many believe that from this Horā System, the present practice of dividing a day and night into 24 hours was adopted. Also, from Sanskrit horā, English hour, Latin hora and Greek ora (ωρα) have been derived.

Did you know? Sankalpam ( संकल्पम) సంకల్పం that we read every day during pooja talks about time. We actually tell the current day from the beginning of time for our purpose.

Think about this part of sankalpam: “Sweta Varahakalpe, Vivsvata Manvantare, Ashtavinshan mahayuge (శ్వేతా వరాహకల్పే, వైవస్వతమన్వంతరే, అష్టావింశన్ మహాయుగే) (स्वेता वराहकल्पे, वैवस्वत मन्वन्तर, अष्टविंशन महायुगे)”

The above describes the time elapsed since the creation began. Go back to the macro measurement of time image given before and notice the term ‘Manwantara”.

That image is reproduced again.

Earth inside a celestial sphere

Img Courtesy: By Prithwis (Own work) [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)%5D, via Wikimedia Commons

There are 14 Manvantaras, check what is the 7th one called, color-coded in Blue below.

  1. Svaayambhuva — son of the self-born (here began the creation), 02. Svaarochisha — son of the Self Shining, 03. Uttama — Son of the Most High, 04. Taamasa — Son of Darkness, 05. Raivata — son of wealth, 06. Chaakshusha — son of the vision (this was the Quirlung instead of the milk ocean), 07. Vaivasvata — Vaivasvata is the son of the Sun God. <—- We currently live here., 08. Arka Saavarni (or Savarnika) — stands with the Sun God in relationship, 09. Daksha-Saavarni — son of the rituals, 10. Brahma-Saavarni — son of Brahma, 11. Dharma-Saavarni — Son of the Eternal Law, 12. Rudra-Saavarni — son of the Destroyer, 13. Deva-Saavarni — Son of the Shining, and 14. Indra-Saavarni — son of the mighty Indra.

Next Steps

Have you ever wondered what is the reason behind the specific order of the weekdays? Why is it Ravivaram, Somavaram, Mangalavaram etc.? Why not Ravivaram, Budhavaram, Shukravaram?

Do you want to know when a minute repeats after 60 seconds, when an hour repeats after 60 minutes, when a day repeats after 24 hours, why not a month repeat exactly after a particular number of days? Is there such a cyclical system? If so, what is that? Is that followed anywhere?

Quick answer: Yes. There is such a cyclical calendar in India and that’s still used. Let’s discuss that in the next article and yes, it’s part of Jyothisha sastra.

Click here for that article.


  1. Drik Vs Surya Siddhanta: http://www.outscar.com/support/index.php/posts/drik-siddhanta-vs-surya-siddhanta

  2. Ancient origins:http://www.ancient-origins.net/artifacts-ancient-writings/surya-siddhanta-startlingly-accurate-astronomy-book-1st-millennium-bc-020969

  3. Surya Siddhanta System (“SSS”) – Vic DiCara’s Astrology- https://vicdicara.wordpress.com/2011/10/14/surya-siddhanta-system-sss/

  4. Time and Space: https://vicdicara.wordpress.com/2018/03/02/time-space-tropical-sidereal/

  5. Surya Siddhanta- Astronomy http://www.ancient-origins.net/artifacts-ancient-writings/surya-siddhanta-startlingly-accurate-astronomy-book-1st-millennium-bc-020969

  6. Hindu units of time:  https://en.wikipedia.org/wiki/Surya_Siddhanta