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

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to MS. Hence the relative parallax is equal to M'x'—MS =
Difference of the latitudes of the Moon in his original
and deflected positions respectively. Hence
S'n = M'n' — (M'x' — MS) = Brahmagupta's nati+correction
of the difference of the latitudes reversely effected, as
stated by Bhāskara.
In fact, Bhāskara has misread Brahmagupta's correct
procedure, since the latter sought the relative parallax of
the Sun and the Moon.
Instead of adding the latitude at V to the zenith-
distance of V (the arc of the Sun's Dṛk-kṣepa) which
implies additional computation of that latitude, as an
approximate procedure, MS is added to ZV to get ZV' as
an alternate procedure as mentioned by Bhāskara in the
course of the commentary.
Whereas Brahmagupta was seeking relative parallax,
Bhāskara misread that Brahmagupta took M'n' as the nati
and did not effect the correction of (M'x—MS) to obtain
S'n, which Bhāskara took to be the Sphuta-nati. Not
effecting the above correction is interpreted as neglecting
it since the Moon's latitude during the course of an eclipse
is small.