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Part 2- Panchang- Astronomy in Vedanga Jyothisha

Part 2- Wheel of Time – Continued – Panchang

This is a continuation of my previous article on the subject. Click here for part 1.

In our last article, we discussed that time is cyclical. At the end, we asked ourselves a question. When a minute repeats after 60 seconds, when an hour repeats after 60 minutes and when a day repeats after 24 hours, why not a month repeat exactly after a particular number of days?

We also asked ourselves if there is a logic behind the order of the weekday names.

In this section, we’ll discuss the above questions. Hindu calendar has got such a cyclical system, which is based on Soli-Lunar cycle, in which, a month repeats after 30 days.

Panchang – Hindu Soli-Lunar Calendar

Here let’s see where this 30 day month is coming from. But before that let’s understand what is Panchang.

Panchang is a Hindu calendar, which considers both Solar and Lunar cycles. The current Gregorian calendar that is in use is primarily a solar calendar. But Hindu Panchang takes into account both Solar and Lunar cycles. Pancha means 5 and Anga means limbs. So Panchang has got 5 limbs. There are a few different ways in which Panchang is presented in India, but the main timekeeping part is usually the same. These 5 limbs are a set of daily astrological tables that help us track time and hence determine the right time to perform a certain task.

Side note: This does not mean that you need to check every day for every small task like going to work and determine which hour and minute are good to leave home. Panchang gives a high-level understanding of which days are more suitable for what type of activities. We see that in modern lifestyle also. For ex: we usually reserve weekends for fun activities and we tend to plan outdoor activities depending on the weather. So it’s not very surprising or superstitious to plan activities based on the type of the day.

Now coming back to the information in Panchang.

Here’re the 5 limbs.

  1. Vara (7 weekdays)

  2. Nakshatra (27 Lunar Mansions)

  3. Tithi (30 Lunar Days)

  4. Karana (60 Half Lunar Day)

  5. Yoga (27 Soli-Lunar combination)

In this article, we’ll discuss the first 3 limbs; Vara, Nakshatra, and Tithi.

The remaining 2 limbs; Karana and Yoga are advanced concepts and I’ll discuss these in later articles.

Let’s see an example of an entry in a Panchang. Today’s date when I am writing this article is: 25th April 2018. Let’s see a future date in June 2018 in Panchang.

Click on the above link and then click on 28th. You’ll notice the following for 28th June 2018 in the left menu.

Month:  Jyeshtha

Weekday: Guruwar

Paksha: Shukla Paksha

Tithi Purnima upto 10:23

Nakshatra Mula upto 12:22

What does the above mean?

  1. Vara: Means weekday. As per the above, it is Guruwar. Means Thursday (Weekday names and the logic behind that particular order is covered in the following sections of this article)

  2. Nakshatra: Mula. This Naksatra comes under the zodiac sign Sagittarius also known as Dhanu Rasi (Dhanu literally means Bow).  Keep this in mind. I’ll explain the importance of this in the following sections.

  3. Tithi: Purnima. Means full moon day. Paksha: Shukla Paksha. Means brightening moon, i.e. waxing moon.

We usually say the above information as “Guru Vasare, Jyeshta masam, Shukla Paksha Purnima, Mula Nakhatra upto ….[time]”

What is Vara?

Vara refers to a solar day. The solar day is known as dinam in India and it’s considered to be from sunrise to sunrise.  Hence the sun is also known as Dina kara- Dina means daytime, kara means something that’s responsible for daylight, i..e Sun.

Logic Behind The Order of the Weekdays

Before we discuss the weekday order, let’s see why only 7 days in a week? Why not 8 days or 9 days or even 15 days? This is because, there are 7 grahas that are visible to the naked eye that move, the movement of which can be tracked against the backdrop of stationary stars as discussed in the previous article. Hence it’s a 7 day week.

Now, why that specific order? Sunday, then Monday. Why not Sunday, then Wednesday?

Weekday names in Panchang

Now first see what are the names of these weekdays, i.e. Vara in Hindu calendar.

We’ve discussed that 7 weekdays are named after 7 grahas in the solar system that are visible to the naked eye.  May I remind the readers that the word Graha and Planet is not one and the same? Planets are a subset of grahas. Graha means anything that grabs, i.e. that exerts physical influence on the other body. Hence Sun is also known as Graha in Sanskrit.

The weekday names in English and the corresponding names in Sanskrit are given below.

  1. Sunday- Ravi Vara (corresponding graha: Ravi, i.e. Sun)

  2. Monday- Soma vara (Corresponding graha: Soma, i.e. Moon)

  3. Tuesday – Mangala var (named after Mangal graha, i.e. Mars)

  4. Wednesday- Budha Vara (named after Budha graha, i.e. Mercury)

  5. Thursday – Guru Vara (named after Guru graha, i.e. Jupiter)

  6. Friday – Shukra Vara  (named after Shukra graha, i.e. Venus)

  7. Saturday- Shani Vara (named after Shani graha, i.e. Saturn)

Now, why that particular order?

The order of the weekdays is based on the speed of the grahas.

As per Surya Siddhanta, the speed of the grahas (in terms of the number of days they take to complete one revolution around the zodiac) is given below.


Besides the above, we know that ancient Indians knew that Moon takes 27 and ¼ day to travel around the zodiac and the Earth takes around 365.25 days (Sun’s apparent path). So can be thought of as Sun -as 365.25 days.

As per Surya Siddhanta, let’s put the grahas by their relative speeds, fastest to slowest.

Here’s that order.


Using Sanskrit names


Interesting tidbit: Notice that Soma, i.e. the moon is the fastest graha, while Shani, i.e. Saturn is the slowest graha. Did you know that the Sanskrit word Shani literally means slow walker? Hence Saturn is known as Shani in India.

Calculating the order of the week days


In the last article, we have seen that as per Surya Siddhanta, there are 60 ghatis in a day. (24 hours * 60 min)/60 = 24 min. So 1 ghati = 24 min.

The first ghati of the first day is named after the source of light in our solar system, i.e. Sun. Hence the first in a weekday is named after Sun, i.e. Ravi.

Hence the first day is “Ravi varam”, i.e. “Sunday”.

Reordering the grahas starting with Sun, the order looks like the below.

Original order: Fastest to slowest: Mo->Me->Ve->Su->Ma->Jup->Sat, and this repeats after 7 grahas

Reordered list: The above list is reordered starting from the Sun and that will be:


Now, the second ghati of the first day is named after the graha that is next in line after Sun, i.e. Mars, i.e. Mangala graham.

Now the 56th ghati of the first day will be Venus (7 grahas and 56 = 7*8) sarting from Sun including Sun.

Hence, 57th will be Sun. 58th will be Ma. 59th will be Jup and 60th will be Sat.  With that, the day ends and the new day starts.

61st ghati, i.e. the first ghati of the second day belongs to that graha that is the next one after Sat, i.e. Moon.

Hence the second day is named after Moon, i.e. Monday, i.e. Soma varam.

Now again the 56th ghati of the second day will be Saturday as we start from Mo on second day.  57th is Mo. 58th is Me. 59th is Ve and 60th is Sun, then the 61st ghati belongs to Mars. So the 61st ghati of the second day. I.e. the first ghati of the 3rd day will be Mars ghati.

Hence the third day is named after Mars, i.e. Marsday, i.e. Mangalavaram.

You can go on and derive the names of the remaining 4 days. At the end of the 7 days, you’ll notice that 61st ghati of the 8th day will be Sun and we’re back to the start of the week.

The same logic can be applied to 24 hours day as well. It’s just that the grahas are first ordered from slowest to fastest and then reordered starting with Sun. 

i.e Slowest to fastest: Sat->Jup->Ma-Su->Ve->Me-Mo,

then reordered as: Su->Ve->Me-Mo->Sa->Ju->Ma

1st hour of the first day is named after Sun. Hence it’s Ravivaram. The 25th hour of the first day, i.e. first hour of the second day will be for the moon as per the above order (Su->Ve->Me->Mo->Sa->Ju->Ma). 25thgraha will be the moon.  Hence the second day is Somavaram. 25th hour of the second day will be Mars, hence Mangalavaram, etc. This is the only logical explanation that we have for the weekday order, which is based on Surya Siddhanta.

As per, In a verse (1/296) of Yājňavalkya Samhitā, the names of the grahas are given exactly in the order of week days, and hence there is every reason to believe that the names of the grahas in that verse were mentioned particularly as the lords of the seven days of a week.

What is a Masa (Month), Paksha (15 day period), Nakshatra and a Tithi (a particular day)?

For us to understand the logical reason behind the names of the months, paksha and tithi in Hindu calendar, we need to revise our understanding of phases of the moon.

From Wikipedia:

Image courtesy: By Orion 8 – Own work, CC BY-SA 3.0,

We all are aware that as the moon revolves around the earth and as the earth revolves around the sun, the moon goes through waxing and waning phases. 15 day (fortnight) waning period followed by 15 day waxing period and this cycle repeats. So the month length is 30 days consisting of 2 pakshas.

What are Full Moon and New Moon called in Hindu Calendar?

In Panchang,

Full Moon is called Pournami (పౌర్ణమి) or Purnima (पूर्णिमा).

New Moon is  called Amavasya (अमावस्या) (అమావాస్య)

What is Paksha?

In the context of Panchang, paksha refers to the particular fortnight period.

Waning phase is Krishna paksha. Krishna means dark or black.

Waxing phase is called Shukla Paksha and Shukla means bright or white.

What is Nakshatra?

Nakstara is a small group of one or more stars in the zodiac belt. Each nakshatra is 13.33 degrees in space in 360-degree celestial sphere as seen from earth. By dividing the sphere into the manageable chunks, ancient Indians were able to track the movement of a graha from one place to another. Note: Nakshatra is not a star. Nakshatra is asterism, a group of stars, specifically this 13.33-degree space. Why 13.33 degrees? Because it is 360/27. Why 27? Because moon takes around 27 days to complete orbiting the earth and hence it takes around 27 days to complete the 360-degree spherical space as we observe from earth. And in each of these chunks of space, Jothishis use a star as the marker point. Hence the mythology: Moon has 27 Taras as wives. A figurative way of saying that Moon spends one day in each nakshatra. 

What is Zodiac belt?


“ Zodiac belt Zodiac, in astronomy and astrology, a belt around the heavens extending 9° on either side of the ecliptic, the plane of the earth’s orbit and of the sun’s apparent annual path.”

Recall the images below: the first one shows the celestial sphere: The spherical space around earth extending into eternity. The second image below shows the moon’s orbit around earth and the Sun’s ecliptic plane. Zodiacal belt is the 360 degree belt around earth extending 9° on either side of the ecliptic where we can locate all the grahas against the backdrop of the stationary stars.

Image courtesy: By Tfr000 (talk) 20:06, 29 March 2012 (UTC) (Own work) [CC BY-SA 3.0 ( or GFDL (, via Wikimedia Commons

From the Stellarium screenshot, we can notice that moon is a full moon and is close to Sagittarius sign (i.e. Dhanus Rasi, notice the bow?) on 28th June 2018. The nearest star to the moon is mula nakshatra. Mula literally means the centre or ‘the most important one’ in Indian languages. Notice that this is the same day that I used in the beginning of this article to show an entry from Panchang. Now, do you see how Panchang aligns with the actual placements of the grahas in the Sky?

Did you know? Mula nakshatra is at the centre of the Milky Way galaxy? And it’s a very important nakshatra in Vedanga Jyotisha? Nakshatra names are not random. They have a specific meaning.  

Btw: Stellarium is a free software and any astronomy enthusiasts can download it on their computers and play with it to get an idea of how the sky looks like on any given day, past, present or future. Then compare that against the entries in Panchang and you can easily notice that the Panchang is describing the astronomical phenomenon.

Why 27 Nakshatras?

In Hindu calendar, i.e. Panchang, we see that there are 27 nakshatras from Ashvini to Revathi. Why 27? What are these?

As we can see from the above discussion, for someone standing on earth, say in Hyderabad, India, and looking up, to track the moon’s movement, they need to track its movement against the stationary objects in the sky, like stars. So relatively speaking, to locate the moon at a specific point in the sky, Indians use the nearest star or a small group of stars called nakshatra as the marker. So they say that Moon is in that nakshatra, i.e.the moon has that nakshatra in the background. This is the importance of nakshatras. They’re the marker points. So that, you can describe the location of the moon in the 360-degree zodiac around the earth on any given day. Your janma nakshatra in Jyothisha means that Nakshatra where the moon is on the day of your birth. So for someone born on 28th June 2018 (to be born), their Nakshatra will be mula.

Now, why 27 nakshatras? Because moon takes 27 and ¼ days to complete the orbit around zodiac, Indians have decided to divide the zodiac into 27 marker points, one for each day of Moon’s movement.  And, those marker points are the nakshatras.

What about that 1/4 th day, i.e. around 6 to 7 hours period? There is a 28th nakshatra called Abhijit that is used for special purposes to cover that situation. It’s an advanced topic and not covered in this article.

What is Tithi?

Tithi is a complex calculation. It’s derived from the relative positions of Sun and Moon wrt Earth. On Amavasya, i.e. new moon day, Sun and Moon are at a separation of 0 degrees as seen from earth at a particular time. We can say that they overlap. From that point onwards, as time passes, the Sun and the  Moon appear to diverge from each other by a certain degree. Notice that moon’s phases are formed by Earth’s and Moon’s rotations and revolutions, and it takes 30 days from New Moon to the next New Moon. So, the Sun and the Moon take 30 days to complete a 360 degree separation, i.e. to come to the point where they overlap again. That means, per day approximately, the degree of separation increase by 12 degrees. 360/30= 12 degrees. The time it takes for the increase in this 12-degree separation is called Tithi. Each tithi is measured by a 12° movement of the Moon away from the Sun.

From: This is because on average the Moon moves 13° a day while the Sun moves 1°. This creates an average daily separation of 12°. However, the lunar day represented by the tithi may be shorter or longer than an actual day.

The tithis between Amavasya and Purnima are named after the number of days passed since new moon and full moon.

Refer to the image below.

Image courtesy: By Orion 8 – Own work, CC BY-SA 3.0,

Notice that from Amavasya, i.e. the new moon day, the moon is gradually appearing to be increasing in size as we approach Purnima, i.e. the full moon day. Again from that point, the moon gradually reduces in size as the days progress towards Amavasya again. The first tithi after Amavasya is called Pratipadi or Padyami and again the first tithi after Purnima is called Pratipadi. These names coincide with the number of days passed since Amavasya or Purnima. For Ex: 6th tithi after Amavasya or Purnima is called Shashti. 7th tithi is called Saptami. Shasti literally means 6 and Saptami literally means 7. So by observing the sky, you will know the Tithi. If you’re in the 6th day of Waxing phase, then it’s is ‘Shukla Paksha Shasthi’ and if you’re in the 6th day of Waning phase, then it’s Krishna Paksha-Shashti.

Hence, you don’t need a calendar to tell the date in the Indian system. You just need to look up at the sky and you can figure out based on moon’s phases. So the Hindu calendar, i.e. Panchang is literally describing the astronomical phenomenon, i.e the relative positions of Earth, Sun and Moon including the backdrop of stars.

Also note: Since the zero degrees separation between the moon and the sun as seen from earth can happen at any time of the day, not necessarily at sunrise on Amavasya, the given tithi can start at any time during the day. This will end at 12-degree separation after approximately 24 hours (actually the length of this lunar day changes and averages to 24 hours). This is the reason, sometimes we see that there are two tithis on a given day and the confusion arises as to when to celebrate a given festival. For layman purposes, when we say 28th June 2018 is Purnima, we mean, that’s the tithi at the time of sunrise on 28th June.

What’s in a name? Logic behind Hindu month names

Contrary to the Gregorian calendar, Hindu month names are not named after kings or warriors. They’re named after the markers in the sky, i.e. the nakshatra that is nearest to the moon on full moon day. So again, it’s purely an astronomical explanation.

Refer to the following image again.

Image courtesy: By Orion 8 – Own work, CC BY-SA 3.0,

A given month in Hindu calendar starts the day after amavasya, i.e. the new moon day and ends on the day of next amavasya. Hence there are exactly 30 days in Hindu month. With in that 30 day period, whatever the nakshatra the full moon is closest to is used to name that whole month. For ex: In a given month, say the full moon at night appears to be closest to Jyeshta nakshatra, then that month is known as Jyeshta masam. Masam means month. Similarly if in a given month, the full moon happens to be near Vishaka nakshatra, then that month is known as Vaishaka masam etc. Since it’s a 360 degree zodiac, 360/30=12, we’ve got 12 months in Hindu calendar. That means in a given year, we have got 30*12 = 360 days.

What about the extra 5.25 days that the earth takes to complete its revolution around Sun? Since Hindu calendar is a Soli-Lunar calendar, they do have a correction for this called ‘Adhika masa”, means leap month, similar to leap year. Every 32.5 months, they repeat a month with the same name (adhika masam) as the following real month (nijam masam) to align the calendar with the seasons. Otherwise, the seasons and the months will go out of sync.

Food for thought: Did you ever wonder what is Jataka chakram? Does it have any astronomical significance? How is it drawn?

Answers to the above questions will be provided in my next article. Stay tuned.


Origins of Jyotisha :

Astronomy for Astrologers #1: Four Types of Years & Sankranti: Ernst Willhelm,

Weekday order explanation:

Another reference:

Seven day week explanation:

Hindu units of time:

Translation of surya siddhanta:

Samkhya and Jyothisha:

Physical astronomy and surya siddhanta:

Vedic time system:– Kala ganana, Shiva, Shakti (AKA Purusha-Prakriti)

Gregorian calendar:

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