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

xlviii सिद्धान्त दर्पण
days. Hence, accepting Bhaskara's year, we should
have 50° 24+7".31 or 57",55 as the precessional rate.
Bhaskara does not state in his Siromani any rate
deduced by him, but evidently supports Munjala's
rate of 59".9. Moreover, his adoption of the rate of
60" a year in his Karana-kutuhala leaves no doubt
in our mind as to the rate he used.
Similarly, Ganesa, author of Grahalaghava,
makes the year of 365.25856 mean solar days, which
is thus longer by 0.00219 days. He ought to have
therefore made the precessional rate 50".24+7".86
or 58".10 instead of 60" as he has done.
Chandrasekhara accepts the length of the year
of the Surya-Siddhanta, and gives 57".615 as the
precessional rate (S.D.VI.75). This is just less than
the rate we have assumed above by 58".68-57". 62
or 1"06. I was surprised to find this close
approximation, and could not but ask him the data
from which he derived the rate. In reply, he said
that finding the Surya-Siddhanta and the Siromani
make the ayanamsa either shorter or longer than
that observed, he was for some time in a fix about
the rate to be followed. Fortunately, while he was
studying Jata-karma-paddhati with the help of the
commentary called Jatakalankara written by
Suryadeva some 800 years ago, he accidentally
found a passage in which the commentator recorded
the ayanamsa as it was observed by him on a
particular day of a particular year. This find itself
is not less valuable than Chandrasekhara's rate. He
gives however, 22°26' as the ayanamsa for the year
we have taken for discussion.
Munjala appears to be the earliest writer who
has given the date of the year of no ayanmsa, as
well as the rate of precession observed by him. He