Which is accurate? Thiru Ganita (Tiru Kantia), Panchangam or Vakyam or Surya Siddhanta Panchangam?

Source/Reference: http://www,mypanchang.com/

What is Panchanga?

Indian sages were very good in astronomy, astrology, spirituality, medical science and other fields. They used to closely monitor the movements of the earth (the Sun with respect to the earth), the moon, and other planets. They (have) set up observatories with the help of wealthy kings, and they used various yantras (machines) to measure time. The day was measured from sunrise to sunrise. The calendar they made was based on the daily movements of the sun and moon at the time of sunrise. This knowledge has been carefully passed down to us from generation to generation and this calendar is commonly known as the ‘Panchangam’.

Panchangam means “pancha” (five) and “anga” (elements). These five elements are: Vaar (Day), Tithi (Date), Nakshatra (Star), Yoga, and Karana (Half-Tithis). This is what is known as panchangam, panchangamu, panchang, jantri and various other names. They holy sages used this panchangam to find good and bad times during the year. A modern panchangam also lists the daily planetary positions.

The Vaar (Day) is measured from one sunrise to the next sunrise. There are seven vaars: Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, and Saturday. The Tithi (we also know them as the phases of the moon) is merely an angle between the sun and the moon to increase by 12 degrees. Unlike the western calendar, tithi or vaar can never be exactly 24 hours in length. Tithis begin at varying times of the day and vary in duration from approximately 19 to approximately 26 hours. There can be more than one tithi during the day. These thithis are known as Prathama, Dwitiya, Tritiya, …etc ….. Pournima, Amavasya. There are fifteen tithis in the bright half (Shukla pakasha) ending with the full moon or Pournima and fifteen tithis in the dark half (Krishna paksha) ending with Amavasya. Their end times are shown in the panchangam. The moon completes a full rotation around the earth in roughly 27 to 29 days, visiting every constellation around the earth. There are 27 constellations or Nakshatras and the position of the moon gives us the daily nakshatra (star). Each 13 degrees and 20 minute division of the zodiac is called a Nakshatra. The moon’s movement is not constant, hence giving us the varying lengths of time it spends in each nakshatra. This could be, again, from 19 to 26 hours. The Yoga is the sum of all the longitudes of the sun and the moon. This sum is divided into 27 equal parts and each part is known as one Yoga. The Karana are the half tithis. There are 11 Karanas. Four of them are fixed and the other 7 are repeating karanas.

How panchangam is caluculated?

The panchangam calculation requires two important heavenly bodies – the sun and the moon, and will be as accurate as how these heavenly bodies are calculated. In ancient times, there were many methods of calculating them. The most ancient one is Surya Siddhanta, another is the Vakyam Siddhanta and the later one is the Driga Ganita (Thirukanitha). The Vakyam is an ancient system where planetary motions are described in simple sentences (hence the vakya). The author of Surya Siddhantha mentions that one should observe the sky and make necessary corrections to planetary formulae (Bija samskar) in order to make an accurate panchangam.

The difference between Thiruganita, Vakyam and Surya Siddhanta

This has not been done in 1500 years! The last update was done in the fifth century. Bhaskaracharya, Maharishi Vashistha and Varahamihira have said to make the panchangam as per Drika ganita (which means the results that can be observed using your eyes). If you calculate Venus and Saturn using Vakyam and look in the sky to try and measure the angle between them, it’s not the same result as the Vakya Siddhanta gives you). Now the question is - if you were to buy curtains for your windows, you’ll take measurements and get them accordingly. We will not buy something that is shorter or longer. The very same way, if you use an algorithm to make the panchangam where you cannot observe the position of the moon and sun in the sky, would you even use it? The moon’s motion is very erratic and needs lots of corrections to arrive at accurate readings. How can you define the moon’s motion in one simple sentence where modern astronomers make pages and pages of corrections? The Moon requires corrections in the algorithm every 72 years. The Surya Sidddhantam has not been updated in 1500 years and the Vakyam Siddhanta has not been updated either. The eclipse calculations in the Vakya panchangam and others are copied from the Drika ganita calculations. This has created great confusion in people’s mind. Which one is accurate? The Drika Ganita relies on modern calculations using spherical trigonometry or NASA’s JPL. The inaccuracies in the Vakyam and Surya Siddhatam calculations can have errors of up to two - four hours in thithi and nakshatra, yoga, and karana end times, along with planetary positions.

Why do we require panchangam for different cities?

Most people buy the Panchangam from India and use it everywhere in the world. This is a wrong practice and one could lead to people observing festivals on wrong days and at wrong times abroad. Each festival has a different set of rules about when to observe them. Hindu festivals are generally based on the Thithi and/or Nakshatra as per the lunar calendar (& some as per the solar calendar). For example, Ganesh Chaturthi is Bhadrapada Shukla Chaturthi Madhyahna purvavidha vyapini. Each thithi begins and ends at the same instant all over the world. After correcting for the time zones, the thithi will begin/end at different local times in different parts of the world. The next thing is to decide if the tithi is visible during the specified time. This is done by using local sunrise, local sunset and local moonrise times. Since India has little variation in terms of sunrise/sunset, a panchangam computed for one area of the country is generally usable throughout the country. For example - on a given day if Chaturthi end time is 2:30 PM in India. Hence, UK will observe the chaturthi end time of 9:00 AM. This clearly indicates in the United Kingdom that the Chaturthi tithi is not prevailing during madhyahana kala (noon time) but it does prevail in India. Hence, the UK will celebrate Ganesha chaturthi on the previous day, as the chaturthi prevails during the noon on the previous day (chaturthi start time is 9:30 am in the UK.) What is important is to observe the festival at the right time in your location. If you blindly use the Indian calendar published in India, it won’t be any good to you as the festival observance dates might change due to local sunrise, sunset, moonrise, time differences etc. The panchang available in India only prints end times in Indian standard times. You need to convert them to your local standard time and use local sunrise and sunset to find out when it can be observed. Most common mistakes people do is observing pradosha and ekadashi vrata on wrong days by following the Indian panchangam printed in India.

Panchangam and Festivals

Ekadashi has two rules: Smartha and Vaishnava. The Smarta rule is simple – ekadashi should be visible at the time of local sunrise. The vaishnava follows ekadashi that is not contaminated by dashami thithi. That means, ekadashi should be prevailing two hours before sunrise. Now, if you follow the Indian panchangam abroad, and apply standard time differences, ekadashi might fall (in some cases) a day before India. Hence, people end up fasting on dwadashi rather than on ekadashi. Likewise for Pradosha Vratam, Trayodashi might be prevailing on the previous day in the United Kingdom when compared to India. Now, if you use the Vakya panchangam or the Surya Siddhanta panchangam, then their tithi end times are off by a couple of hours. Hence people could observe festivals on wrong dates. The bottom line is to follow Drika panchangam for your location. Just using any panchanga published in India for abroad isn’t a good idea!

Panchangam and Muhurtha

Muhurtha is another thing alltogether. Which requires combination of Vaar, Tithi, Nakshatra, Yoga, Karana, Local sunrise, local Lagna (rising sign on the eastern horizon -- which keeps changing every couple of hours as earth rotates on it's own axis it cuts ecliptic on eastern horizon -- This is the first house), etc.... This lagna is always specific to given longitude and latitude. Hence you can't subtract time difference from lagna time in india to arrive the lagna time in foreign country. Timings of lagna will change even in India from place to place and using it in foreign country is out of question even after subtracting time difference. Sun will be always in the first house during the sunrise, during the noon sun will be always in the 10th house, during the sunset always in the 7th house and during midnight sun will be always in the 4th house. So you cannot subtract time difference to arrive at lagna (the 1st house). It will be completely wrong.

Thiruganita and Horoscopes

Most people will cast their loved one's horoscope using thiruganita panchangam. Now I've a hard time understanding the argument that "For festival one should use vakyam because it's divine". The problem is the formulae used in Vakyam are very old and known to rishis at that time. If we use them for festivals then we get error. They say because thithis are apratyaksha (non-visible) and that's why have to use vakyam or surya siddhanta. But if Full moon (Purnima) and the New moon (Amavasya) is the real thing and visible then why to use pambu / vakyam / surya siddhanta panchanga saying tithis and nakshatras are non-visible? Hence always use drika panchangam (Thiruganita panchangam).

http://www.mypanchang.com/ has Drika panchanga for more than 350+ cities all over the world and in many Indian languages. Now in English, संस्कृत, हिन्दी, मराठी, ગુજરાતી, ಕನ್ನಡ, తెలుగు, and தமிழ்.