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

400
any arbitrary moment whatsoever. With this Valana
primarily laid in the Manaikyārdha Vritta, decide the
Krānti Vrittaprachī or the East-West direction of the
eclipse. Thus in the figure V₁ V₂ is this direction. Then
lay off the computed Bhuja along this V₁ V₂ from M, say
MA for the Sammīlana moment or the moment when
totality begins or MC for the Unmīlana moment or the
moment when totality ends or MD for an arbitrary
moment. Draw AR₁ or CR₂ or DE equal to the latitude
at the particular moment, perpendicular to the Valana-
sūtra. In the figure drawn the Valanasūtra is shown to
be the same. This does not mean it will be the same
throughout. It will be changing because the position of
the Ecliptic changes from moment to moment. So Bhās-
kara uses the word ie. 'the respective Valanasūtra'.
Also the latitudes will be differing from moment to
moment as well as the Bhujas both of which are to be
computed for any moment along with the Valana. (The
method of computing the Bhuja was given in verse 15).
Computing the respective Karṇas or the hypotenuses from
the formula K = √(Bhujā² + Kōti²), (Kōti is here the lati-
tude) with centre M and radius equal to the Karṇas, if
arcs be drawn to cut the latitudes, the points of intersection
would be no other than R₁, R₂ or E. Join MR₁, MR₂ and
ME. With centres R₁ and R₂ and radii equal to p - r,
(where p is the radius of the Rāhu-Bimba, and r the
radius of the Moon's disc) if circles be drawn, they just
touch the Moon's disc at F and G which are the points
where totality begins and ends respectively. With centre
E and radius P, if a circle be drawn, that will show what
amount of the disc is shadowed as well as the measure of
the magnitude of the eclipse (defined in verse 11).
Note. In the above commentary and figure we
have depicted MD as the Iṣṭa-Bhuja or the Bhuja at a
given moment, taking a moment prior to the Unmī-
lanakāla, for showing the magnitude of the eclipse.