Garga & Parashara: Forgotten Astronomers of India - Prof RNI and Sudhee in an excellent conversation

[Sunder Chakravarty]

Prof. RN Iyengar & S.Subrahmanya talk on "Garga & Parashara: Forgotten Astronomers of India" is posted on youtube Atharva Forum.

https://youtu.be/o2NRMYlfkWg

A summary of the talk is enclosed. This full conversation, of course, is a lot more instructive and informative - hope your time allows. 

Regards

Sunder

Conversation on Pre-Siddhānta Indian Astronomy - a summary

An excellent conversation between Professor R.N. Iyengar and the interviewer Mr. S. Subramanyam, about pre-Siddhānta Indian astronomy, focusing on the period before the commonly known Siddhānta astronomical texts i.e. much prior to time of Āryabhaṭa - can be found here - and is summarized below.  The discussion builds upon a previous episode, expanding on Vedic observations and their evolution.

### Key Points:

**Vedic Period (4th millennium BCE and earlier):** Initial astronomical observations were likely disrupted by events like comet impacts or storms, leading to more focused celestial observation and ritual practice.  The concept of cosmology and humanity's place in the universe were already present.  The Shishuma constellation (around 3000 BCE) played a significant role.

**Transition Period (3rd-2nd millennium BCE):** This period saw the development of models incorporating Meru (an imaginary axis connecting Earth and sky) and practical applications of astronomical knowledge in rituals and agriculture.  However, detailed records from this period are scarce.

**Lagadha's Calendar (around 1300 BCE):** Lagadha's calendar, while important, lacks information on planets, eclipses, and comets, leaving a gap in the record.

**Parāśara and Vṛddhagārgā Traditions:** Professor Iyengar focuses on the works of Parāśara and Vṛddhagārgā, two ancient astronomers whose works predate the 5th-6th century BCE.  Parāśara's work, primarily known through later commentaries, contains a list of 26 comets with their inter-arrival times, spanning approximately 1200 years. This suggests a continuous tradition of observation stretching back to around 2500-2600 BCE. Parāśara used a solar zodiac based on seasons.

**Vṛddhagārgā's Work:** Professor Iyengar’s research into Vṛddhagārgā's manuscripts (including the Mahāsalilā section) reveals a wealth of astronomical information, including a solar zodiac similar to Parāśara's, details on nakshatras (constellations) and their constituent stars, and information on the sidereal period of the moon. The Mahāsalilā is dated to around 1600 BCE. Vṛddhagārgā's work provides more detail than Lagadha's and includes information about Mars's retrograde motion.  The manuscripts reveal a more sophisticated understanding of astronomical phenomena than previously assumed.

**Dating Methods:** Dates for various astronomical texts and epochs were determined using computer simulations and a minimum error method. This involved comparing the positions of stars and nakṣatras described in the texts with their calculated positions at different times, identifying the time period with the least discrepancy. This analysis suggests a maghādi epoch (summer solstice-based) around 1800 BCE, based on the Brahmāṇḍa Purāṇa/Maitrāyāṇīya Āraṇyaka, and a Śraviṣṭhādi epoch (winter solstice-based) around 1300 BCE, based on Ādityacāra. A Ṛtusvabhāva epoch (based on months and solar nakṣatras) is estimated around 800 BCE.

**Epochs and Solstices:** The analysis revealed distinct astronomical epochs characterized by the use of either the summer solstice (maghādi) or the winter solstice (śraviṣṭhādi) as a reference point. The shift in reference points and the evolution of methods for calculating the position of the Sun reflect the ongoing development and refinement of astronomical knowledge over time.

**Agastya (Canopus):** The observation of Agastya (Canopus), a southern star, is discussed as evidence of early astronomical knowledge. Its visibility in the Kurukshetra region suggests observations dating back to 4000 BCE.

**Mahābhārata and Purāṇas:** The discussion touches upon the Mahābhārata and Purāṇas, which contain astronomical information interwoven with narrative traditions, requiring careful analysis to separate detailed observations from other narrative elements.

**The Concept of Time:** The discussion highlights the evolution of the understanding and measurement of time, including the concept of *thithi* (instantaneous time) and its implications for astronomical calculations.

### Conclusion:

Professor Iyengar highlights the Mahāsalilā section of the Vṛddhagarga text as a crucial source for understanding pre-Siddhānta astronomy. He emphasizes the 100 questions posed to Vṛddhagarga by Vishvamitra within this section as being particularly important. These questions, covering the origins of the universe, planets, comets, rivers, mountains, and the nature of time and seasons, reflect a deep curiosity and a holistic approach to understanding the cosmos. The detailed answers provided within the Mahāsalilā offer valuable insights into the reasoning and methods employed by ancient Indian astronomers.

The Mahāsalilā, written in prose, resembles Vedic Brahmaṇa texts in style, further emphasizing its antiquity and connection to earlier traditions. Professor Iyengar's work on this text demonstrates the value of meticulous manuscript study, cross-referencing multiple sources, and employing modern analytical techniques (like computer simulations and minimum error analysis) to interpret ancient astronomical data. His approach serves as a model for future researchers, underscoring the need for a multidisciplinary approach that combines textual scholarship with scientific analysis to unravel the complexities of ancient scientific traditions. The Mahāsalilā, therefore, provides not only astronomical insights but also valuable lessons in research methodology for the modern scholar.

The conversation reveals a continuous and sophisticated tradition of astronomical observation in India, extending far beyond the commonly accepted starting point of Siddhānta astronomy. Professor Iyengar’s research challenges established narratives, suggesting a much earlier and more complex development of Indian astronomy, with significant advancements in the understanding of celestial movements, timekeeping, and meteorological phenomena. The discovery and analysis of previously unknown or understudied texts are crucial to this revised understanding.