Varāhamihira-Paddhati: Varāhamihira's Eclipse Methods

The astronomer who weighed five rival schools, chose the best, and declared Rāhu was not the cause

Varāhamihira did not just compute eclipses; he judged the methods. In the Pañcasiddhāntikā he set five rival astronomical schools side by side, including Greek-derived ones he named openly, and chose the most accurate. And on the cause of eclipses he was blunt: Rāhu is not the cause. Yet he kept the ritual. Learn the method of the great synthesiser.

Five Manuals on One Desk

Around the middle of the sixth century, at Ujjain, the astronomical capital of India, a scholar sat with a problem no single calculation could solve. On the desk before Varāhamihira lay not one astronomy but five, five different siddhāntas, five rival manuals, each with its own parameters, its own methods, its own way of computing where the Sun and Moon would be and when they would be eclipsed. They did not fully agree. Some were old and rough; some were sharp and new; some had come from far away. The question was not how to compute an eclipse. It was which of these five methods to trust.

Most astronomers picked a school and followed it. Varāhamihira did something rarer and more modern. He put all five side by side, compared them, judged their accuracy, and wrote the comparison down. The result was the Pañcasiddhāntikā, the "Treatise of the Five Siddhāntas", one of the most valuable works in the history of Indian astronomy, and a model of the critical, comparative mind at work.

The Five, Weighed and Ranked

The five schools Varāhamihira compared were the Paitāmaha, the Vāsiṣṭha, the Pauliśa, the Romaka, and the Saura (or Sūrya) Siddhānta. He did not treat them as equally sacred. He weighed them by how well they matched the sky, and he said plainly which were better. The Saura he judged the most accurate, the Pauliśa accurate, and the Romaka close to it; the old Paitāmaha and the Vāsiṣṭha he found far from the truth. He built his own methods largely on the better three.

This is doxography as science: not choosing a school by loyalty, but ranking methods by their results. It is exactly the temperament that makes an astronomy self-correcting, and it is why the Pañcasiddhāntikā preserves, for us, the methods of schools whose original texts are otherwise lost.