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

466 obtain the rising time of the planet p, which occured before that of q, Vilōmalagna or an anterior point of time is to be computed, and this is done by subtracting the asus of Akṣa-Dṛk-karma from the rising time of q. The rest follows on these lines of elucidation. Verse 9. The planet rises at the time known as its Udayalagna (which is to be computed as aforesaid) and it sets at the time known as its Astalagna (which is also to be computed as mentioned before). Comm. Clear. Verse. 10. During the night, at a given moment, the computed Udayalagna of the planet is less than the particular lagna of the moment, ie, if the longitude of the Udayalagna is less than that of the current lagna, and also if the Astalagna of the planet computed is greater than that of the then current lagna ie. if the longitude of the Astalagna is greater than that of the current lagna, the planet is visible ie. above the horizon. In the case of the Moon, however, if he is not eclipsed by the rays of the Sun, he may be visible even shortly after Sunrise or a little before Sunset in contradistinction to a planet which could not be seen at all during day time (except perhaps Venus). When a planet is visible, his gnomonic shadow could be computed. (This does not mean that the gnomon casts a shadow of the planet but means that its zenith- distance could be computed according to the methods described in Tripraśnādhikāra. Comm. Clear. Verse 11. To obtain the shadow, the time that has elapsed after the rise of the planet is to be known. If it be required to find the gnomonic shadow of the planet, then the current lagna and the Udayalagna of the