Panchasidhantika, written by Varahmihir is based on?

Varahamihira's main work is the book Panchasiddhantika ("[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 Siddhanta.