To
the Western scholars, Indian Astronomy is mysterious. Let us see what astro
scholars have said about IA.
Dennis Duke, of Florida State University suggests that Indian Astronomy
predates Greek Astronomy
"The planetary models of ancient Indian mathematical astronomy are
described in several texts.1 These texts invariably give algorithms for
computing mean and true longitudes of the planets, but are completely devoid
of any material that would inform us of the origin of the models. One way to
approach the problem is to compare the predictions of the Indian models with
the predictions from other models that do have, at least in part, a known
historical background. Since the Indian models compute true longitudes by
adding corrections to mean longitudes, the obvious choices for these latter
models are those from the Greco-Roman world. In order to investigate if there
is any connection between Greek and Indian models, we should therefore focus
on the oldest Indian texts that contain fully described, and therefore
securely computable, models. We shall see that the mathematical basis of the
Indian models is the equant model found in the Almagest, and furthermore, that
analysis of the level of development of Indian astronomy contemporary to their
planetary schemes strongly suggests, but does not rigorously prove, that the
planetary bisected equant model is pre-Ptolemaic" says he.
The earliest Indian Planetary Models are two sets from the writer Aryabhata,
both dating from 6th Century AD.
1) The Sunrise System , after the Epoch, which is taken from the sunrise of
18th Feb 3102 (Arya Paksha ).
It appears first in Aryabhatiya
2) The Midnight System, after the Epoch, which is taken from the midnight of
17/18 FEB 3102 ( Ardha
Ratri Paksha ). It
appears first in Latadeva's
Soorya Siddhanta
The Local Meridien is taken as Lanka, Longitude 76 degrees, Latitude 0
degrees.