TIME ELAPSED SINCE SUNRISE 83 oblique ascension of that sign and divide by 30, the resulting asus denote the asus of the oblique ascension of the traversed portion of the sign occupied by the rising point of the ecliptic. (Also subtract the traversed portion of the sign occupied by the rising point of the ecliptic from the longitude of the same point). Then from the resulting longitude subtract as many preceding signs as there are up to the Sun; and find out the asus of the oblique ascensions of those signs. These asus together with those (obtained above) when added with the asus of the oblique ascension of the untraversed portion of the Sun's sign give the asus (elapsed since sunrise) in the day and (enable us to know) the asus (elapsed since sunset) in the night. Dividing them by 6 and then by 60 are obtained the ghatis, vighatis, and asus (of the time elapsed during the day or night).¹ This rule is the converse of that given in stanzas 30-32. It actually gives the method for finding the time elapsed since sunrise. When, therefore, the Sun's longitude is given for sometime in the night and it is required to find the time elapsed since sunset, then the time elapsed since sunrise obtained according to the above rule should be diminished by the length of that day, or, as says the commentator Parameśvara, the given longitude of the Sun should be increased by six signs and then should be applied the above rule. In case the given quantities be (i) the longitude of the rising point of the ecliptic and (ii) the Sun's longitude at sunrise and the problem be to find out the civil time elapsed since sunrise, the above rule should be applied by treating the Sun's longitude for sunrise as the first approxi- ¹This rule is found also in SuSi, iii. 50-51; BrSpSi, iii. 21-23; LBh, iii. 20; Ś¡DVṛ, I, iii. 13; Siśe, iv. 19(ii)-22(i); SiŚi, I, iii. 5-7(i). The ghațis, vighatis, and asus are related by the following relations: 1 asu 4 seconds, 6 asus = 1 vighați (=24 seconds), 60 vighatis = 1 ghați (=24 minutes),
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