सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

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that 360 solar days constitute a solar year and no defini-
tion is given for a single solar day. This definition of
solar days, though apparently artificial, has some signi-
ficance, namely that the difference of the solar and lunar
days defined above constitutes 159330000000 Adhikamāsas
in a kalpa at the rate of 30 tithis per month. In other
words the difference between the solar and lunar days, is
the number of tithis that the luni-solar reckoning gains
over the solar. This topic will be dealt with later.
Verse 9. The number of civil days in a kalpa is
equal to 1577916450000; the number of the diurnal revolu-
tions of the stars minus the number of sidereal revolutions
of any particular planet constitute the days of that parti-
cular planet with respect to the earth.
Comm. The civil days in a kalpa are evidently the
number of Sun-rises. These are as mentioned before the
difference of the number of diurnal revolutions of the stars
and the number of the sidereal revolutions of the Sun.
By analogy, the number of the days of a particular planet
with respect to the earth or what is the same the number
of risings of that planet in a kalpa as seen from the earth,
is the difference of the number of the diurnal revolutions
of the stars and the number of the sidereal revolutions of
that planet in a kalpa. Thus we have Saura-Ku-dināni,
Chāndra-Ku-dināni, Bhauma-Ku-dināni etc, where the
word ‘ Ku ’ means the earth. The Saura-Ku-dināni are
the civil days defined before. It will be noted that the
Chāndra-Ku-dināni are not the lunar days.
Verse 10. The number of Adhikamāsās or intercalary
months in a kalpa is equal to 1593300000 and the number
of Dina-Kshayas is 25082550000.
Comm. A luni-solar year as per Cāndramāna ie the
luni-solar reckoning consists of twelve lunations; as such
its length falls short of that of the solar year by 11 days
3 ghatis, 52 Vighatis and 30 Sukshmaghatis. If both the