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

282 Fig. 54 parallel to the horizon. then Ox = Iṣṭa-S'anku = Oα + ax = Un-mandala S'anku + Iṣṭa yaṣṭi. ar = yaṣṭi. In the Southern hemisphere Oα, the Unmandala S'anku will be below the horizon so that Iṣṭayaṣṭi decreased by the Unmandala S'anku will be Iṣṭa-S'anku. Thus we have the method of obtaining the Iṣhta- S'anku from the Unnata Kāla as detailed above. We shall see what this process means in modern terms. Unnatakāla-Charakāla = ⊙P̂A − AP̂E (Fig. 21) = ⊙P̂E where ⊙ is the foot of the declination circle of the Sun e in any arbitrary position in his diurnal path. But ⊙P̂E = QP̂E − QP̂⊙ = 90−h where h is the hour angle of the Sun. Thus Sutra = H sin (90−h) = H cos h I