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

186
This result is to be subtracted from the position of B
to get the position of S. If the position B′ which is the
setting position at Lanka, and if we have to get S′ the
local setting position, in as much S′ is later than B′ by
the same arc, we have to add the above result to the posi-
tion B′ to get S′. Here the asus in a day is given to be
21659 and not 60 × 60 × 6=21600 because the mean daily
motion is during the course of the Sāvana day i.e. the true
solar day and not during the course of a sidereal day of
21600 asus. The Sāvana day exceeds the sidereal by the
time taken by the arc moved by the Sun during that day
which is very approximately 59′. Since a minute of arc
of the Equator rises in an asu i.e. in 4″, so 59′ of the Sun's
motion is covered in 59 asus which is to be added to 21600
asus of the sidereal day to get the Sāvana day approxi-
mately. It will be noted that this correction of chara in
the planetary positions is due to latitude of the place and
if the latitude is zero, it need not be done. Also if δ = 0,
it need not be done, for, then, the Sun or the celestial
body whose δ = 0 will be rising at E itself in which case
the chara EA will be zero.
Verses 54, 55. The H sines of 30°, 60° and 90°, being
squared and decreased by the squares of their respective
declinations, the square-root of the differences being taken,
and the result being multiplied by the radius, is to be
divided by the respective H cosines of the declination.
The first of the three results, the difference of the second
and the first and the difference of the third and the second
will give us the rising times of what are called the Sāyana
rasis of Mesha, Vrishabha and Mithuna; their reverses
will then give the rising times of the next three; then
the original ones those of the next three and again then
reverses those of the last three.
Comm. There are twelve Rasis in the Zodiac of equal
interval. Measuring from r, and taking arcs of the