The Inspiration
Brahma taught the Vedas and vedāñga (which includes Jyotiṣa) to his mind-born son Nārada. Some jyotiṣa teachings are available in the Nārada saṁhitā. In turn devarṣi Nārada passed this knowledge to Maharṣi Saunaka. Maharṣi Parāśara was the disciple of Maharṣi Saunaka and received the complete knowledge of the Vedas and vedāñga from his spiritual master in addition to substantial learning from his most illustrious grandfather Maharṣi Vasiṣṭha.
His magnum opus Bṛhat Parāśara Horā Śāstra is in the traditional form of dialogue with his śiṣya Maharṣi Maitreya wherein the humble disciple makes sincere queries and is taught the complete Horā śāstra.