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

868
Fig. 73
MN is therefore the latitude of the Moon. Since the lati-
tude is not the same at the moment of first contact and
that of the last contact, the figure drawn does not
represent the true figure but only a figure drawn on the
supposition that β remains the same and C₁ Moves relative
to M. From the figure C₁N² = (P+r)² − β² = C₂N² I
The Sthiti-Khanda defined in this verse is the time
taken by C₁ to reach the position N ie. the position at
the moment of opposition, and again from the position N
to the position C₂. The velocity of C₁ relative to M is
no other than the excess of the velocity of, the Moon over
that of the Sun. (The velocity of the Earth is the relative
velocity of the Sun with respect to the Earth and this is
equal to the velocity of the shadow moving along the
ecliptic). So, the time taken by C₁ to reach the position
of N relative to the Moon is equal to [ 60 × √(P + r² − β²) ] / [ m₁ − s₁ ]
Similarly the time taken by the centre of the shadow from
N to C₂ ie. from the point of opposition to the moment