Pancha-siddhantika (IAST: Pañca-siddhāntikā) is a 6th-century CE Sanskrit-language text written by astrologer-astronomer Varāhamihira in present-day Ujjain, India.
[1] Indian writers on astrology and astronomy generally chose an epoch year close to the date of composition of their texts, in order to facilitate correct astronomical calculations.
This is because according to Amaraja, the author of a commentary on Brahmagupta's Khanda-khadyaka, Varāhamihira died in 587 CE (Shaka year 509).
If Varāhamihira wrote Pancha-siddhantika in 505 CE even at the young age of 25, he must have been over 105 years old at the time of his death, which seems exceptionally high to these scholars.
[13] Notable mathematical concepts in the Pancha-siddhantika include:[7] Like Brahma-gupta, Varāhamihira rejects Aryabhata's view (now universally accepted) that the earth revolves around the sun.