Varahamihira

Daivajna Varāhamihira (Devanagari: वराहमिहिर) (505–587), also called Varaha or Mihira, was an Indian astronomer, mathematician, and astrologer who lived in Ujjain. He is considered to be one of the nine jewels (Navaratnas) of the court of legendary king Vikramaditya (thought to be the Gupta emperor Chandragupta II Vikramaditya).

Pancha-Siddhantika

Varahamihira's main work is the book Pañcasiddhāntikā (or Pancha-Siddhantika, "[Treatise] on the Five [Astronomical] Canons) dated ca. 575 CE 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 native Indian as well as Hellenistic astronomy (including Greek, Egyptian and Roman elements).
The 11th century Arabian scholar Alberuni also described the details of "The Five Astronomical Canons":

"They have 5 Siddhāntas:

* 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.

Brihat-Samhita
Main article: Brihat-Samhita

Varahamihira's other most important contribution is the encyclopedic Brihat-Samhita.

Varahamihira also made important contributions to mathematics. He was also an astrologer. He wrote on all the three main branches of Jyotisha astrology:

* Brihat Jataka - is considered as one the five main treatises on Hindu astrology on horoscopy.
* Daivaigya Vallabha
* Laghu Jataka
* Yoga Yatra
* Vivaha Patal
* His son Prithuyasas also contributed in the Hindu astrology; his book "Hora Saara" is a famous book on horoscopy.