Achyutha Pisharadi
Achyuta Pisharodi (c. 1550 at Thrikkandiyur (aka Kundapura), Tirur, Kerala, India – 7 July 1621 in Kerala) was a Sanskrit grammarian, astrologer, astronomer and mathematician who studied under Jyeṣṭhadeva and was a member of Madhava of Sangamagrama's Kerala school of astronomy and mathematics. He is remembered mainly for his part in the composition of his student Melpathur Narayana Bhattathiri's devotional poem, "Narayaneeyam". Works. He discovered the techniques of 'the reduction of the ecliptic'. He authored "Sphuta-nirnaya", "Raasi-gola-sphuta-neeti" ("raasi" meaning zodiac, "gola" meaning "sphere" and "neeti" roughly meaning "rule"), Karanottama (1593) and a four-  chapter treatise "Uparagakriyakrama" on lunar and solar eclipses. Narayaneeyam. Pisharati is known to have scolded and provoked an errant Narayana to take up the Brahmin's duties of prayer and religious practices. He accepted Narayana as his student. Later when Pisharati was struck with paralysis (or rheumatism by another account), Narayana, unable to bear the pain of his dear guru, by way of Gurudakshina took the disease upon himself. As a result, Pisharati is said to have been cured, but no medicine could cure Narayana. As a last resort, Narayana went to Guruvayur and requested Thunchaththu Ramanujan Ezhuthachan, a great  devotee of Guruvayoorappan, to suggest a remedy for his disease. Ramajunan Ezhuthachan advised him to compose a poetical work on the Avatars (incarnations) of Lord Vishnu beginning with that of Matsya (Fish). Narayana composed beautiful slokas in praise of Lord Guruvayurappan and recited them before the deity. He was soon cured of his disease. The book of "slokas" written by Narayana were named Narayaneeyam. The day on which Narayana dedicated his Narayaneeyam to Sri Guruvayurappan is celebrated as "Narayaneeyam Dinam" every year at Guruvayur.