Varāhamihira was an astronomer and mathematician who studied and Indian astronomy as well as the many principles of Greek, Egyptian, and Roman astronomical sciences.
He was also known as Varaha or Mihira, was an who lived in Ujjain. He is considered to be one of the nine jewels (Navaratnas) of the court of legendary ruler Vikramaditya.
He was the first one to mention in his work Pancha Siddhantika that the ayanamsa, or the shifting of the equinox is 50.32 seconds.
His book gives us information about older Indian texts which are now lost. The work is a treatise on mathematical astronomy and it summarises five earlier astronomical treatises, namely the Surya Siddhanta, Romaka Siddhanta, Paulisa Siddhanta,Vasishtha Siddhanta and Paitamaha Siddhantas. It is a compendium of Vedanga Jyotisha as well as Hellenistic astronomy (including Greek, Egyptian and Roman elements). He was the first one to mention in his work Pancha Siddhantika that the ayanamsa, or the shifting of the equinox is 50.32 seconds.
The 11th century Arabian scholar Alberuni also described the details of "The Five Astronomical Canons":
- Sūrya-Siddhānta, ie. the Siddhānta of the Sun, composed by Lāṭadeva,
- Vasishtha-siddhānta, so called from one of the stars of the Great Bear, composed by Vishnucandra,
- Pulisa-siddhānta, so called from Paulisa, the Greek, from the city of Saintra, which is supposed to be Alexandria, composed by Pulisa.
- Romaka-siddhānta, so called from the Rūm, ie. the subjects of the Roman Empire, composed by Śrīsheṇa.
- Brahma-siddhānta, so called from Brahman, composed by Brahmagupta, the son of Jishṇu, from the town of Bhillamāla between Multān and Anhilwāra, 16 yojanas from the latter place.
"They [the Indians] have 5 Siddhāntas:
His other most important contribution is the encyclopedic Brihat-Samhita. It covers wide ranging subjects of human interest, including astrology, planetary movements, eclipses, rainfall, clouds, architecture, growth of crops, manufacture of perfume, matrimony, domestic relations, gems, pearls, and rituals. The volume expounds on gemstone evaluation criterion found in the Garuda Purana, and elaborates on the sacred Nine Pearls from the same text. It contains 106 chapters and is known as the "great compilation".
- Other Works:
The Romaka Siddhanta ("Doctrine of the Romans") and the Paulisa Siddhanta ("Doctrine of Paul") were two works of Western origin which influenced Varahamihira's thought. Though this view is controversial as there is much evidence to suggest that it was actually Vedic thought indigenous to India which actually first influenced Western astrologers and subsequently came back to India reformulated.
A comment in the Brihat-Samhita by Varahamihira says: "The Greeks, though foreign, must be honored since they have shown tremendous interest in our science....." ("mleccha hi yavanah tesu samyak shastram kdamsthitam/ rsivat te 'p i pujyante kim punar daivavid dvijah".
As a Mathematician his contribution is mainly in the trigonometry.