Bhāskara II

Bhāskara II was a Vedic astronomer. In his work, he praises the work of ancient astronomers as 'abundant in intelligent expression'. His purpose is to improve upon their work and 'fill in some lacunae'. One of the things he does is refine the work of Brahmagupta on koṭi and karṇa. He also fixed an error in Brahmagupta's calculation regarding the geocentric parallax of the Moon.

In his, he gives the revolutions of the planets in a kalpa (~4.3 billion years)