The Blackwell Companion to Hinduism

The following quotation is from the R.gvedic recension:

The Vedas advanced for the sake of sacrificial rituals. And the sacrificial rituals

were prescribed in the order of time. Therefore one who has known this science of

prescription of time, namely, astronomy, has known sacrificial rituals. (A ̄rca-

jyautisam 33, in Dvivedin 1907)

This verse gave a strong motivation to those who devoted themselves in the study
of astronomy. Thus, for instance, Bha ̄skara II, the author of the Lı ̄la ̄vatı ̄and
one of the most popular astronomer-mathematicians in India, wrote in the
middle of the twelfth century:

First of all the Vedas advanced through the activities of sacrificial rituals, while

sacrificial rituals are said to be dependent on time. Since knowledge of time is from

this science, therefore astronomy is said to be a branch of Vedic studies.

(Siddha ̄ ntas ́iroman.i; Grahagan.ita ̄dha ̄ ya 1.1.9)

The main purpose of the jyotis.aveda ̄n.gawas the preparation of a calendar in
order to fix the date of sacrificial rituals. Nothing is written on planets. The cal-
endar described here represents the earliest stage of Indian calendrical tradition.
Almost all the important elements which characterize the Indian calendar are
already found in this literature. The main feature of this calendar is the five-year
cycle which is clearly stated as:

A year is 366 days, 6 seasons, 2 ayanas, and 12 solar months. This, multiplied by

five, is a yuga. (Ya ̄jus.ajyautis.am 28cd, in Dvivedin 1907)

(The number of) sa ̄vanamonths, lunar months, sidereal months (in a yuga) are 61,

62, and 67 (respectively). A sa ̄vana [month] has 30 days. A solar year is a turn of

the stars. (Ya ̄jus.ajyautis.am 31)

This statement can be tabulated as follows. Items in [ ] are not explicitly stated.

1 year =366 days =6 seasons

= 2 ayanas =12 solar months

1 sa ̄vana month =30 days

5 years =60 solar months [=1,800 solar days]

= 61 sa ̄vanamonths [=1,830sa ̄vana days]

=62 synodic months [=1,860tithis]

=67 sidereal months

This system requires two intercalary months (adhima ̄sas) in every five years, in
other words, one intercalation in every two and a half years. This is clearly men-
tioned in Kaut.ilya’s Arthas ́a ̄stra(2.20.66). We can interpret the word sa ̄vanahere
as equivalent to the modern adjective “civil”, although there were different mean-
ings of this word and this verse has been subject to different interpretations.^1

calendar, astrology, and astronomy 377