पृष्ठम्:महाभास्करीयम्.djvu/२५१

166 A rule for finding the true nati: 28-32. Multiply the drkksepajyas (of the Sun and the Moon), obtained by the method of successive approximations, (severally). by the Earth's semi-diameter, and divide (the resulting products) by the true distances in yojanas (of the Sun and the Moon respectively): the quotients are in minutes of arc (the parallaxes in latitude of the Sun and the Moon). Take their difference, provided that the madhyajyas of the Sun and the Moon are of like direction; in the contrary case, take their sum: thus are obtained the minutes of the avanati (or nati). (As regards the direction of the nati) take the direction of the Moon's (madhyajyā). ECLIPSES Multiply the Rsine of the longitude of the Moon minus the longitude of the Moon's ascending node by 270, and then divide that product by the Moon's true distance in minutes. Thus is obtained the true celestial latitude of the Moon. This increased by that (nati) (provided the two are of like direction) is the true nati. In case they are of unlike directions, take their difference. The difference is then called the (true) nati. Thus is obtained the true avanati (or true nati) for the middle of the eclipse as determined from the drkksepa and the true latitude of the Sun and the Moon for the time of apparent conjunction (literally, the time of geocentric conjunc- tion corrected for the lambana-difference). The term nati or avanati means "parallax in latitude". When used alone in connection with a solar eclipse, it denotes the difference betweeu the parallaxes in latitude of the Sun and the Moon. The true nati is the Moon's latitude corrected for the nati (i.e., Moon's apparent latitude). It denotes the arcual distance of the Moon from the Sun's apparent orbit due to parallax. The formula given for the nati for the time of apparent conjunction of the Sun and the moon is nati = Moon's dṛkksepajya X Earth's semi-diameter Moon's true distance in yojanas Sun's drkkṣepajyā × Earth's semi-diameter Sun's true distance in yojanas