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

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corrections namely Bhujāntara, Chara and the Udayāntara
as well.
Comm. The correction of chara arises out of the
difference between the equatorial risings and local risings
of the mean Sun. The local mean Sun pertaing again to
uniform motion along the celestial equator Udayāntara
has to be effected for l—a, ie. for the local mean Sun on
the ecliptic. Thus we have obtained the planetary posi-
tions for the local mean Sun-rise and to obtain them for
the True Sun-rise, Bhujāntara is to be effected.
Verse 65. An alternative method of effecting the
Udayāntara correction.
Double the H sine of the Sāyana longitude of the Sun
derived out of the smaller H sin-table, being multiplied
by the daily motion of the planet and divided by 270 and
the result in seconds of arc is to be corrected in the plane-
tary position positive or negative according as the Sun is
in the even or odd quadrants.
Comm. (1) In symbols the correction indicated is
(m H sin 2l) / 270 where m is the planet's mean daily motion in
minutes of arc, l the longitude of the mean Sun, and
H sine is taken where the radius = 120. In the commen-
tary under the verse, Bhāskara adds 'Each quadrant of
the eclipse rises (at the equator) in ¼th of a day but
each Rāśi does not rise in 1/12 of a day. Since this
Udayāntara correction vanishes when the Sun is at the
ends of quadrants it must be construed that this
correction increases positively or negatively from the
beginning of the quadrant to the middle and decreases
from the middle to the end of a quadrant. Saying that a
particular Rāśi rises at the equator in n nādikās is only
an approximate statement since the Rāśi does not rise
uniformly. That is why astronomers like Aryabhata
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