(b. Trkkaṇṭiyūr [Sanskrit, Kuṇḍapura], Kerala. India, ca. 1550; d. Kerala, 7 July 1621)
Acyuta was a member of the Piṣāraṭi community, which is a section of the Ampalavāsi community and is traditionally employed in looking after the external affairs of temples. Hestudied astronomy under Jyeṣṭhadeva (ca. 1500–1600), a Nambūtiri Brāhmaṇa of the Par̤an̆n̆oṭṭu family in the village called Ālattūr, who wrote the Yuktibhāṣā based on the Tantrasañgraha of Nīlakaṇṭha Somasutvan. Jyeṣṭhadeva and Nūlakaṇṭha were pupils of Dāmodara, the son and student of Parameśvara, who founded the Dṛggaṇita school of astronomy (for an account of this school, see my essay, V A 2). Acyuta’s patron was Ravivarman, King of Veṭṭattunād (Sanskrit, Prakāśa; 1595–1607). He was a scholar in grammar (his famous pupil Nārāyana Bhaṭṭatiri [1560-ca. 1646] refers to him in his Prakriyāsarvasva), poetics, and medicine, as well as in astronomy and astrology. In the field of astrology, there existed in his school a long line of scholars writing in Malayalam.
Acyuta wrote the following works dealing largely with astronomy.
1. Praveśaka. This is an introduction to Sanskrit grammar in about six hundred anuṣṭubh stanzas. It was edited, with a commentary, by P.S. Anantanarayana Sastri, as Vol. II in Cochin Sanskrit Series (Trippunithura, 1938).
2. Karaṇottama. This is a work on astronomy in five chapters and about one hundred verses; it deals with the computation of the mean and true longitudes of the planets, with eclipses, and with the vyatūpātas of the sun and moon. Acyuta himself wrote a commentary on it. It was published as Vol. 213 of Trivandrum Sanskrit Series (Trivandrum, 1964).
3. Uparāgakriyākrama. This is a treatise in four chapters on lunar and solar eclipses which was completed in 1593. There is a commentary on it in Malayalam.
4. Sphuṭanirṇaya. This is a work on astronomy in six chapters, written before the Rāśigolasphuṭānūti.
5. Chāyāṣṭaka. This is a short astronomical text in eight verses.
6.Uparāgaviṃśati. This is a manual in twenty verses on the computation of eclipses. It was published with a Malayalam commentary in Vol. II of the Ravivarma Sanskrit Series (Trippunithura, 1954).
7. Rāśigolasphuṭānūti. This work in fifty verses is concerned with the reduction of the moon’s true longitude in its own orbit to the ecliptic. Since in this work Acyuta quotes not only the Sphuṭanirṇaya but also the Uparāgakriyākrama, it is clear that the Rāśigolasphuṭānūti was written after 1593. It was edited and translated into English by K.V. Sarma as Adyar Library Series, Paper 29 (Madras, 1955); reprinted from Brahmavidyā, 18 (1954), 306–335.
8. Veṇvārohavyākhyā. This Malayalam commentary on the Veṇvāroha of Mādhava of Sañgamāgrama (ca. 1340–1425) was written at the request of Netranārāyaṇa, a spiritual head of the Nambūtiri Brāhmaṇas. The Veṇvāroha deals with the calculation of the tithis and nakṣatras. The text and its commentary have been edited by K.V. Sarma in Vol. III of the Ravivarma Sanskrit Series (Trippunithura, 1956).
9. Horāsāroccaya. This is an adaptation in seven chapters of the Jātakapaddhati of Srūpati. The relationship to it of a Malayalam commentary on the Jātakapaddhati entitled Horātantraṃ Parijbhāṣa remains uncertain.
Further discussion of Acyuta Piṣāraṭi may be found in S. Venkitasubramonia Iyer, “Acyuta Piṣāroṭi; His Date and Works,” in JOR Madras, 22 (1952–1953), 40–46; and K. Kunjunni Raja, The Contribution of Kerala ot Sanskrit Literature (Madras, 1958), pp. 122–125, and “Astronomy and Mathematics in Kerala,” in Brahmavidyā, 27 (1963), 158–162.