Glimpses from the Āryabhaṭasiddhānta

Abstract

In a paper entitled “Āryabhaṭa I’s astronomy with midnight day-reckoning” published by me nine years ago in the Gaṇita (Vol. 18, No. I, 1967), I had adduced concrete and conclusive evidence to show that Āryabhaṭa I, the celebrated author of the Āryabhaṭīya, wrote one more work on astronomy which was known as Āryabhaṭasiddhānta. Whereas in the Āryabhaṭīya the day was reckoned from one sunrise to the next, in the Āryabhaṭasiddhānta the day was reckoned from one midnight to the next. This latter work of Āryabhaṭa which adopted midnight day-reckoning was first mentioned by Brahmagupta (628 AD) of Bhinmal in Rajasthan, who was so much impressed by its wide popularity that he epitomised the teachings of this work in his calendrical work bearing the title “Food prepared with sugar candy” (Khaṇḍakhādyaka).