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

383
Fig. 81
PL = δ since PA = 90° and LM = 90°. The Āyana Valana
K̂MP is measured by the arc ML where ML is an arc of
the Grahakṣitija or the horizon of the planet M (ie. the
circle with M as centre and 90° as radius drawn on the
sphere or what is the same the great circle whose pole is
M). PB is an arc of the small circle parallel to KL which
is an arc of a great circle. Then in the Jina Vritta
sin PB = sin PK × sin P̂KB = sin ω sin (90 - λ) = sin ω cos λ
∴ sin KL = sin ω cos λ/cos PL = (sin ω cos λ) / (cos δ) = sin PMK.