The Hindu calendar used in ancient times has undergone many changes in the process of regionalization, and today there are several regional Indian
calendars, as well as an
Indian national calendar. In
Pakistan it is called 'desi' or native calendar. Most of these calendars are inherited from a system first enunciated in
Jyotish Vedanga of Lagadha, a late BCE adjunct to the
Vedas, standardized in the
Surya Siddhanta (3rd century CE) and subsequently reformed by astronomers such as
Aryabhata (499 CE),
Varahamihira (6th c. CE), and
Bhaskara (12th c. CE). There are differences and regional variations abound in these computations, but the following is a general overview of hindu lunisolar calander.
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