सिद्धान्तदर्पण (महामहोपाध्याय सामन्त चन्द्रशेखर सिंह - नग्न-नेत्र खगोल वेध एवं गणित महाकोश)

Introduction li
Bhaskara. From this he might have obtained the
Saka year 444 as the starting year, and also the rate
of 60 seconds a year, making the amount 16°37′ in
Saka 1442.
It remains to notice the data 421 Saka given by
some minor authors. This is obviously based upon
the Surya-Siddhanta's with its annual rate of 54,
making 20°55′ as the amount of present ayanamsa.
Chandrasekhara has not recorded the data
which furnished him the rate, knowing howerver,
his ayanamsa and rate, and calculating backwards,
we arrive at Saka 415.
So far we have obtained the following figures:
Sakabda Rate per year
Munjala 425 56″.828
Satananda 437 57.295
Bhaskara 423 56.624
Chandrasekhar 415 57.61
Mean 425 57.09
Having regard to the nature of the data ve
cannot expect a closer approximation than that
shown above. We may therefore fairly take the
mean of the dates, as well as the rates. On account
of obvious inaccuracy in the data of Ganesa the date
and rate obtained from him cannot be rightly
included. Neither will his date, if corrected increase
the weight to be attached to the mean to be
calculated from the above figures. We might,
however, include the data 421 Saka given by certain
weriters. Indeed, it will be seen that dates of the
starting years are of two classes; one somewhere
near 450 Saka, and the other, 421 Saka. But the