| From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, p. 816 |
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Courtesy of 
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Muñjāla
Narahari Achar
Alternate
name
Mañjula
Flourished Deccan, (India),
possibly 900
Muñjāla
was the author of a remarkable work, the Laghumānasa, which is
an abridged version of a larger work called Bṛhanmānasa. Very little
is known about the life of Muñjāla, except that he was a brāhmaṇa belonging to the Bhāradvājagotra,
and that he lived in Deccan.
The
Laghumānasa was very popular among the astronomers from Kerala,
and it is mentioned by Bīrūnī.
Parameśvara wrote
a commentary on it, and quotations from it are found in the works of Bhāskaracārya
and Munīśvara.
The Laghumānasa appears to be the first siddhāntic
text to treat the precession of the equinoxes. Muñjāla gives the number
of “ayana” revolutions to be 199,669 in a kalpa, and the “ayanāāśa”
to be 6° 54' in 932 and the year of
zero “ayanāāśa” as 522. Muñjāla was the first Indian astronomer
to introduce corrections to the Moon's equation that account for what today
is called evection. Muñjāla anticipates Bhāskaracārya in understanding
that the sine and cosine are related in a way that we would express today
by saying the derivative of a sine function is a cosine function.
Selected References
Bose, D. M., S. N. Sen, and B. V. Subbarayappa (1971). A
Concise History of Science in India. New Delhi: Indian National Science
Academy.
Dikshit, S. B. (1896). Bhāratīya Jyotisha.
Poona, English translation by R. V. Vaidya. 2 pts. New Delhi: Government of
India Press, Controller of Publications, 1969, 1981.
Muñjāla. Laghumānasa, edited with the commentary
of Parameśvara by B. D. Āpaǭe. Ānandāśrama
Sanskrit Series, 123. Poona; 1944; 2d ed. Poona, 1952. (There is also an English
translation with notes by N. K. Majumdar, Calcutta, 1951.)
Pingree, David. Census of the Exact Sciences in Sanskrit.
Series A. Vol. 4 (1981): pp. 435a–436a; Vol. 5 (1994): 312b. Philadelphia:
American Philosophical Society.
Shukla,
K. S. (1990). A Critical Study of the Laghumānasa of Mañjula.
New Delhi: Indian National Science Academy.