Lalla

For other people named Lalla, seeLalla (disambiguation).

Lalla
Born	720 Gujarat
Died	790 India

Lalla(c.720–790 CE) was an Indianmathematician,astronomer,andastrologerwho belonged to a family of astronomers. Lalla was the son of Trivikrama Bhatta and the grandson of Śâmba.He lived in central India, possibly in theLāṭaregion in modern southGujarat.Lalla was known as being one of the leading Indian astronomers of the eighth century. Only two of his works are currently thought to be extant.

His best-known work is theŚiṣyadhīvṛddhidatantra( "Treatise which expands the intellect of students" ). This text is one of the first major Sanskrit astronomical texts known from the period following the 7th-century works ofBrahmaguptaandBhāskara I.It generally treats the same astronomical subject matter and demonstrates the same computational techniques as earlier authors, although there are some significant innovations, such that Lalla’s treatise offers a compromise between the rival astronomical schools of his predecessors,Āryabhaṭa Iand Brahmagupta.It is within theŚiṣyadhīvṛddhidatantrathat the earliest known description ofperpetual motionis described.

The other extant work by Lalla is theJyotiṣaratnakośa( "Treasury of Jewels" ), a treatise on catarchic astrology. This work is one of the earliest known Sanskrit astrological works for determining auspicious and inauspicious times. No edition of this text has ever been published while the known manuscripts are incomplete.

In his work, Lalla drew on his predecessorsBrahmagupta,andBhāskara I.In turn, he influenced later generations of astronomers, includingĀryabhaṭa II,Śrīpati,Vaṭeśvara,andBhāskara II(who later wrote a commentary on theŚiṣyadhīvṛddhidatantra).

He followed the Āryapakṣa or the school ofĀryabhaṭa(continued by Bhāskara I), but divided themahāyugain the traditional way, following the Brāhmapakṣa school ofBrahmagupta.

Works

• Śiṣyadhīvṛddhidatantra:The most extensive extant exposition of the views of the Āryapaksa school. It contains twenty-two chapters divided into two books:

I. On the Computation of the Positions of the Planets

1. On the mean longitudes of the planets.
2. On the true longitudes of the planets.
3. On the three problems involving diurnal motion.
4. On lunar eclipses.
5. On solar eclipses.
6. On the syzygies.
7. On the heliacal settings and risings of the planets.
8. On the shadow of the moon.
9. On the lunar crescent.
10. On planetary conjunctions.
11. On conjunctions of the planets with the stars.
12. On the pātas of the sun and moon.
13. Conclusion.

II. On the Sphere

1. On graphical representations.
2. On the construction of the celestial sphere.
3. On the principles of mean motion.
4. On the terrestrial sphere.
5. On the motions and stations of the planets.
6. On geography.
7. On erroneous knowledge.
8. On instruments.
9. On certain (selected) problems "

• Jyotiṣaratnakośa:A popular book on astronomy in India
• A commentary onBrahmagupta'sKhandakhadyaka,now lost

References

• O'Connor, John J.;Robertson, Edmund F.,"Lalla",MacTutor History of Mathematics Archive,University of St Andrews
• K. V. Sarma."Lalla."Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures,ed.Helaine Selin,Dordrecht: Kluwer Academic Publishers, 1997, p. 508.
• Plofker, Kim (2009),Mathematics in India (book),Princeton University Press,ISBN978-0-691-12067-6
• "Lalla."Complete Dictionary of Scientific Biography. Vol. 7. Detroit: Charles Scribner's Sons, 2008. 582-583. Gale Virtual Reference Library. Web. 3 June 2013.
• Bracher, Katherine.The Biographical Encyclopedia Of Astronomers[Electronic Resource] / Edited By K. Bracher... [Et Al.]. n.p.: New York; London: Springer, 2006., 2006. UNIV OF OKLAHOMA LIBRARIES's Catalog. Web. 6 June 2013.