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

399
Verse 30 and first half of 31. Geometrical depiction
of the eclipse at the beginning and end of totality and
also of the magnitude of the eclipse.
The Bhuja is to be laid from the centre of the Moon
along its Valanasūtra or the line indicating the direction
of the ecliptic; the latitude is to be drawn from the end
of the Bhuja and perpendicular to the Bhuja. The hypo-
tenuse is to be drawn from the centre of the Moon. Taking
the point of intersection of the latitude (Kōti) and the
hypotenuse, as centre and radius p equal to that of the
eclipsing body, if circles be drawn, from these circles could
be known the points where totality begins and ends as
well as the magnitude of the eclipse at any given moment.
Or these could be found in another way as follows.
Comm. The method given above for depicting the
phases of an eclipse geometrically, could be applied for any
moment during the course of the eclipse and depends
upon before-hand computed Bhuja and Kōti. Refer to
fig. 90. Let M be the centre of the Moon's disc. Mark
Eω the East-west line drawn through M. Compute the
Valana for the required moment, either for the moment
when totality begins or for that when totality ends or for
Fig. 90