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

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Rectification of this time, when β is considered as
varying will proceed on the same lines as before.
Verse 13. Rectification of the times of Sparsa-Sthiti-
Khanda and Mōksha-Sthiti-Khanda.
From the position of the Moon and that of the Node
obtained for the moment of opposition, have to be com-
puted their positions for the moment of first contact and
those for the moment of last contact. For this, (T × v) / 60
is to be subtracted and added respectively to the positions
at the moment of opposition of the Moon and Node, where
T is the time of the Sparsa-Sthiti-Khanda, and v the daily
motion (of the Moon or the Node as the case may be).
From these positions β has to be computed for the moment
of first contact and that of last contact, and from this β
the time of Sparsa-Sthiti-Khanda and Mōksha-Sthiti-
Khanda have to be rectified by the method of successive
approximation.
Comm. From fig. 75, C₁ N₁ and C₂ N₂ are the dist-
ances gained by the Moon over the centre of the shadow
so that to get their correct values β₁ and β₂ are to be used
and not β. Hence β₁ and β₂ are to be computed using T
the time of Sparsa-Sthiti-Khanda and that of the Mōksha-
Sthiti-Khanda which are taken to be equal in the first
instance. Since T is the time taken as a first approxi-
mation, β₁, β₂ are also approximate in the first instance.
From these β₁, β₂ T is to be rectified and in this rectifi-
cation, we have T₁ and T₂ differing, as the times of Sparsa-
Sthiti-Khanda and Mōksha-Sthiti-Khanda. From these
rectified times again β₁, β₂ are further to be rectified and
from them again T₁, T₂ are to be further rectified. This
procedure is to be continued till constant values are
obtained for T₁ and T₂.
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