The Blackwell Companion to Hinduism

yogais based on the “sum” of the longitude of the Sun and the Moon. The
present author has written a computer program for pañca ̄n.gabased on the
Su ̄ ryasiddha ̄nta. The program is available at my web page (http://www.kyoto-
su.ac.jp/~yanom/).

4.3 Mathematical astronomy

Sanskritization The planetary astrology of Hellenistic origin gave a strong moti-
vation for Indian people to learn Greek astronomy. How they got access to Greek
astronomical texts and which texts were studied are not known yet. When the
first Sanskrit astronomical text based on Greek astronomy appeared it was
already in a well established form. The text was the A ̄ryabhat.ı ̄yaof A ̄ryabhat.a
(born in ad476). During the interval of 300 years between the first Yavanaja ̄taka
and the A ̄ryabhat.ı ̄yaIndian astronomers must have been occupied with the task
of Indianizing and Sanskritizing Greek astronomy. The astronomical texts of this
period were all lost, but fortunately we have Vara ̄hamihira’sPañcasiddha ̄ntika ̄
(Neugebauer and Pingree 1970) where the five astronomical schools which
were known in his time were summarized. They are: the Paita ̄hamasiddha ̄nta, the
Vasis.t.hasiddha ̄nta, the Romakasiddha ̄nta, the Paulis ́asiddha ̄nta, and the Su ̄ ryasid-
dha ̄nta. Vara ̄hamihira evaluates them by the following words:

The Paulis ́a is accurate, that which was pronounced by Romaka is near it; the

Sa ̄ vitra (i.e. the Su ̄ rya) is more accurate; the remaining two have strayed far away

(from the truth). (PS 1.3; Neugebauer and Pingree 1970: 27)

In fact the Paita ̄mahasiddha ̄nta, belonging to the veda ̄n.gatradition, was obsolete
already in Vara ̄hamihira’s time. What characterizes the Vasis.t.hasiddha ̄ntais
period relations and linear zigzag functions which are probably of Babylonian
origin. No geometrical method is used in these two older schools of astronomy.
ThePaulis ́aandRomaka, which are highly regarded, are of western origin as the
names suggest. These two texts were, according to Vara ̄hamihira’s own state-
ment, commented upon by a La ̄t.adeva. The author of the Su ̄ryasiddha ̄nta, the
most accurate of the five siddha ̄ntas, is not known. This text is different from the
later and more popular Su ̄ ryasiddha ̄nta.

388 michio yano

sunrise sunrise sunrise sunrise sunrise

d7 d8 d8 (adhika) d9

t6 t7 t8 t9 t10

Figure 18.5: Adhikadina.