Vijayanandi 

Born: about 940 in Benares (now Varanasi), India
Died: about 1010 in India Vijayanandi (or Vijayanandin) was the son
of Jayananda. He was born into the Brahman caste which meant he was
from the highest ranking caste of Hindu priests. He was an Indian
mathematician and astronomer whose most famous work was the
Karanatilaka. We should note that there was another astronomer named
Vijayanandi who was mentioned by Varahamihira in one of his works.
Since Varahamihira wrote around 550 and the Karanatilaka was written
around 966, there must be two astronomers both named
"Vijayanandi". The Karanatilaka has not survived in its
original form but we know of the text through an Arabic translation
by alBiruni. It is a work in fourteen chapters covering the standard
topics of Indian astronomy. It deals with the topics of: units of
time measurement; mean and true longitudes of the sun and moon; the
length of daylight; mean longitudes of the five planets; true
longitudes of the five planets; the three problems of diurnal
rotation; lunar eclipses, solar eclipses; the projection of eclipses;
first visibility of the planets; conjunctions of the planets with
each other and with fixed stars; the moon's crescent; and the patas
of the moon and sun. The Indians had a cosmology which was based on
long periods of time with astronomical events occurring a certain
whole number of times within the cycles. This system led to much work
on integer solutions of equations and their application to astronomy.
In particular there was, according to Aryabhata I, a basic period of
4320000 years called a mahayuga and it was assumed that the sun, the
moon, their apsis and node, and the planets reached perfect
conjunctions after this period. Hence it was assumed that the periods
were rational multiples of each other. All the planets and the node
and apsis of the moon and sun had to have an integer number of
revolutions in the mahayuga. Many Indian astronomers proposed
different values for these integral numbers of revolutions. For the
number of revolutions of the apsis and node of the moon per mahayuga,
Aryabhata I proposed 488219 and 232226, respectively. However
Vijayanandi changed these numbers to 488211 and 232234. The reasons
for giving the new numbers is unclear. Like other Indian astronomers,
Vijayanandi made contributions to trigonometry and it appears that
his calculation of the periods was computed by using tables of sines
and versed sines. It is significant that accuracy was need in
trigonometric tables to give accurate astronomical theories and this
motivated many of the Indian mathematicians to produce more accurate
methods of approximating entries in tables. Article by: J J O'Connor
and E F Robertson
Source:www.history.mcs.standrews.ac.uk/Mathematicians



