Nādi Astrology is a form of astrology practiced in Tamil Nadu and adjacent regions in India. It is based on the belief that the present lives of many humans were foreseen by Hindu sages in ancient times.

Agastya was a revered Indian sage of Hinduism. In the Indian tradition, he is a noted recluse and an influential scholar in diverse languages of the Indian subcontinent. He is regarded in some traditions to be a Chiranjivi. He and his wife Lopamudra are the celebrated authors of hymns 1.165 to 1.191 in the Sanskrit text Rigveda and other Vedic literature.