Aryabhatta (476-550 A.D.) was born in Patliputra in Magadha, which in modern India is Patna in Bihar. According to many people he was born in the southern part of India especially Kerala and later he moved to Magadha at the time of the Gupta rule, which is also known as the golden age of India.
Aryabhatta was particularly popular in southern part of India, where many other mathematicians also wrote commentaries.
The Arya-siddhanta, is known through the writings of Aryabhata’s contemporary Varahamihira which is a lost work on astronomical computations. It is also known through the work done by other later mathematicians and commentators including Brahmagupta and Bhaskara I. The Arya-siddhanta work appears to be based on the older Surya Siddhanta, and it uses the midnight-day-reckoning, as opposed to sunrise in Aryabhatta. This also contained a description of several astronomical instruments, the gnomon (shanku-yantra), a shadow instrument (chhAyA-yantra), possibly angle-measuring devices, semi-circle and circle shaped (dhanur-yantra / chakra-yantra), a cylindrical stick yasti-yantra, an umbrella-shaped device called chhatra-yantra, and water clocks of at least two types, bow-shaped and cylindrical.