5 Siddhantas
Astronomical knowledge was very well developed during the Vedic and Vedang periods and was further developed and updated in subsequent periods.
सिद्धान्तis one of the sub-branches of Ganit Skandha.
For various branches of Astronomy see
https://intrestingcosmos.blogspot.com/2024/03/ -of 01 March 2024
Knowledge of the position of the Sun, Moon, and other planets was required for calendrical, religious, and daily rituals.
The history of astronomical works can be assessed from the oldest known group of 5 ancient सिद्धान्त known as पंचसिद्धांतिका written by Varahmihira (500 CE)
These 5 सिद्धान्त are
पितमहः,वसिष्ठ,रोमक,पौलिश ,सौर
Varahmihira in his पंचसिद्धांतिका says that the सिद्धान्त written by Paulisa is fairly accurate, but not as accurate as Saura/Surya Siddhant. The accuracy of others is doubtful.
These Siddhantas outline methods for calculating the mean positions of the Sun and Moon, as well as the orbital periods of other planets. They provide a comprehensive explanation and calculations regarding mean motion मध्यमाधिकारः /adhikara on mean places and the average number of revolutions of the planets. Additionally, the texts discuss the length of the year, the concept of yugas, and methods for intercalation and synchronization.
For example
One of the couplets describes a method of calculating the length of the day. It says
द्विघ्नं शशिरस्(61)भक्तं द्वादश हिं दिवसमनम्
" Multiplying (the number of days elapsed after WS or the days to go before the end of Ayana, beginning with SS ) by 2 and dividing by 61. Add 12 (Muhuratas) to the quotient, and the result will be the length of the day"
Surya Siddhanta of the पंचसिद्धांतिका group had assumed the commencement of Yuga at midnight and that it postulates the Yuga system. ( It is assumed that all planets including the Sun and The Moon were together on this day)@@@. Dixit has confirmed this aspect, by comparing the data of Surya Siddhanta to the actual longitudes, so calculated as per Surya Siddhanta as of 1887.
Al Biruni commented that पौलिश siddhant was compiled by Paulus—ul—Ynani, or Paulus the Greek. Professor Webber refuted his claim, stating that Paulus's work was related to astrology and not astronomy.
Al Biruni states that Surya Siddhant was compiled by Lata. Prof Weber connects it with Ptolmey's works. However, Surya Siddhanta of the पंचसिद्धांतिका group was not complied by Lata . Dixit proves both the contentions incorrect.
पितमहः and वसिष्ठ सिद्धान्त appear to be old, as they are similar in concept to Vedang Jyotish. The other siddhantas appear to be around the pre-Saka period, i.e.,200-50 BCE. Dixit proves Dr Thibaut's argument that their antiquity around 400 CE was wrong.
पितमहः,वसिष्ठ,पौलिश ,सौर,रोमक are as per their chronological order of antiquity.
The Five Modern सिद्धान्त
The elements described by पंचसिद्धांतिका group differ from those in the more modern Sidhantas. They primarily differ in the length of the year and the planets' mean motion, position, number of revolutions etc. The data is updated and more accurate, and hence the epitaph modern.
The five modern सिद्धान्त are वसिष्ठ,रोमक,सौर सोम, ब्रह्म सिद्धान्त . It is not clear if two सोम siddhantas existed.
All five siddhantas declare themselves to be divine and are actually so regarded.Other siddhantas ,such as पंचसिद्धांतिका ,विष्णुधर्मोत्तरः,ब्रह्मसिद्धान्तः are also regarded divine.
Surya Siddhanta is more popular than other siddhantas. It is believed that it was compiled during the second or third century CE.
Surya Siddhant was first translated into English by Dr Ebenzer Burgess in 1860. Prof Whitney further added extensive notes to it. Prof Whitney believed that Hindus borrowed it from the Greeks. However, Burgess clarifies at the end of his book that it was The Greeks who borrowed it from the Hindus
The contents of all the Siddhantas provide explicit astronomical details, making it challenging to summarize the information succinctly. Anyone interested in a detailed study is encouraged to explore the references listed below.
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@@@With the advancement of technology, changing times, and evolving concepts, a new thought process has emerged. The latest astronomy software can now simulate past events and accurately show the positions of the nakshatras and planets.
These new revelations may directly conflict with the findings of ancient scholars, as well as with established beliefs and rituals. More research and studies are needed to uncover the truth.
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References
1. SB Dixit " Bhartiya Jyoti's Shastra" Part 2
2. William Brennand " Hindu Astronomy"
3. Coolebroke Essays.
4. Dr Thibaut's Essays on Surya Siddhanta
5. Dr Ebenzer Burgees's Translation of Surya Siddhant
6. Dr Nilesh Oak talks
