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

17 Comm. A lunation is divided into thirty tithis, which go by the names pratipat etc. of which there are fifteen in the brighter half of the lunation and fifteen in the dark fortnight. The pratipat tithi is that duration of time be- ginning from the moment of New Moon and ending when the Moon has over taken the Sun by 12°; the second tithi named dvitīyā begins at the end of pratipat and lasts upto the point of time when the moon’s elongation is 24° and so on. Thus the tithis are seen to be of unequal length in as much as both the Sun and the Moon have unequal motion. The mean duration of a tithi is seen to be a little less than a civil day since a lunation has ronghly 29½ civil days. There is a convention that the tithi which is current at a Sun-rise will be considered to be the tithi of the whole day. As per this convention it so happens that a tithi lasts just a little after Sun-rise and the next tithi vanishes during the same day so that the next but one will be taken for the next day. This vanishing tithi is known as a Kshaya tithi which is also called a Kshayāba. Again it so happens that a tithi may be current at two consecutive Sun-rises beginning a little before the Sun-rise of the first day and extending a little after the next Sun-rise. Such a tithi is called Dina- Traya or a tithi which touches three days. In this matter if seems as though we have gained a tithi but ultinately as a tithi must be less than a civil day, it so happens that on the average there will be a Kshayāha rongbly in 64 tithis. We shall see more about this matter subsequently. Verse 32. Thus there are nine mānas Mānava, Divya (or of gods), Bārhaspatya (Jovian) paitra, Nākshatra, Saura, Chāndra, Sāvana and Brāhma. But the planetary positions are to be computed by men by their own māna. Comm. Not necessary. Here ends the Adhyāya known as Kāla-māna in the Madhyādhikāra. 2