ब्राह्मस्फुटसिद्धान्त (ब्रह्मगुप्त - शून्य, कुट्टक, बीजगणित एवं सम्पूर्ण २१ अध्याय सान्वय सटीक)

MAJOR LANDMARKS 67
covery of the Vedic era, some of the planets, the twenty-
four nakṣatras, cycle of seasons, concept of leap year,
the dimensions of a yuga, solar and lunar years and the
like.
II. Astronomy of the Vedāṅga, also known as the Vedāṅga
Jyotiṣ. Lagadha is the most prominent figure of this
period (1400 B.C. to 850 B.C.) ; he is the first compiler
of a text on astronomy. In his work, we for the first
time in history find a reference to the Jñeya Rāśi (the
knowable or the unknown quantity) and the Jñāna-
Rāśi (known quantity). He lays the foundations of
astronomical calculations. In his treatise we find a
mention of such subjects as : Solstices (northern and
southern journey of the Sun), increase in days and
nights in the ayanas or solstices, solstitial tithis omis-
sion of tithis, parva rāśi, acceptable and non-acceptable
parvas, addition of day, acceptable parvas, concept of
yoga (a term applied to the joint space which would
be travelled by the Sun and the Moon in a given period
of time on the presumption that these two bodies have
travelled in directions opposite to each other), method
of finding out a nakṣatra on any parva day, distinction
between parva-nakṣatra and tithi-nakṣatra, correlation
of solar and lunar dates, measure of a nāḍikā (unit of
time), nakṣatra of the Sun, yoga and its nakṣatra, parva-
bhaśeṣa and equivalent kalās, solar year, lunar revolu-
tions (risings of nakṣatras) deities of nakṣtras, lunar
and sāvana day differences (āhika māsa), divisions of
a sāvana day and length of day in two ayanas. This
author probably belonged to Kashmir.
III. The period of Siddhāntas : Varāhamihira in his well
known treatise, the Pañcasiddhāntikā, refers to five
Siddhāntas or systems of Astronomy : Paitāmaha,
Vasiṣṭha, Romaka, Pauliśa and Sūrya (Saura). As re-
gards its importance, he gives the first place to the
Sūryasiddhānta, places next the Romaka and Pauliśa,
and declares the remaining two to be definitely inferior
to the former. We do not possess the full treatise of
these Siddhāntas, except the Sūryasiddhānta. Here too,