Indian Astronomy: Contributions and Developments

Overview

• Examination of India's contributions to astronomy over the past 1500 years.
• Focus on the continuity of tradition and development in astronomical principles.

Important Works and Contributions (600 CE - 1200 CE)

• Surya Siddhanta: Ancient text with multiple versions; significant in traditional astronomical practices.
• Varahamihira: Compiled five siddhantas, presenting updated summaries of ancient texts.

Aryabhatta (476 CE)

• Aryabhatiya: Foundational work in mathematical astronomy.
  • Contributions to trigonometry, particularly the sine function.
  • Algorithms for positions of celestial bodies.

Bhaskara I and Brahmagupta

• Detailed explanation of Aryabhatta's works.
• Brahmasputa Siddhanta: Mathematical and astronomical developments.
  • Introduction of quadratic indeterminate equations.

Later Contributions

• Sripati, Bhaskaracharya II: Development of standard calculations, algorithms.
• Kerala School of Mathematics (1200 - 1800 CE)
  • Madhava and others: Contributions to infinite series, planetary theory, and spherical trigonometry.

Aryabhatiya: A Closer Look

• Division into Four Sections:
  • Gitika Pada: Numerical notation and planetary revolutions.
  • Ganita Pada: Mathematical concepts like squares, roots, area calculations, and solving equations.
  • Kalakriya Pada: Time reckoning, calendrical concepts.
  • Golapada: Spherical astronomy, celestial motions.

Key Concepts

• Planetary Revolution and Maha Yuga:

  • Equal duration for all sub-yugas.
  • Establishing February 18, 3102 BCE as the start of the current Kali Yuga.

• Planetary Models:

  • Geocentric model similar to Taiko Brahe’s later model.
  • Introduction of Manda and Shigra Samskara for corrections.

Notable Figures and Texts

• Nilakantha Somayaji: Made corrections to planetary models.
• Ganesha Daivajna, Kamalakara, Chandra Shekhara Samanta: Contributions to astronomy and calendar reform.

Conclusion

• Continuous improvement and formalization in Indian astronomy.
• Aryabhatiya as a pivotal point in developing mathematical astronomy.
• Future discussions to focus on specific elements of Indian calendrical and astronomical systems.