CHAPTER VI VISIBILITY, PHASES, AND RISING AND SETTING OF THE MOON A rule relating to the visibility correction known as aksa-drk' karma : 1-2. Multiply the Rsine of the Moon's latitude by the Rsine of the (local) latitude and divide (the product) by the Rsine of the colatitude. Whatever is thus, obtained should be subtracted from the Moon's longitude in the case of rising of the Moon (i.e., in the eastern hemisphere) and added to that in the case of set- ting of the Moon (i. e., in the western hemisphere), provided that the Moon's latitude is north. When the Moon's latitude is south, the above correction is applied reversely in the cases of rising and setting (both). 1 A rule relating to the visibility correction known as ayana-drk- karma : 3-4. Multiply the (Moon's) instantaneous latitude by the Rversedsine (of the Moon's longitude) as diminished by three signs and then by the Rsine of the (Sun's) greatest declination and divide that (product) by the square of the radius. The result- ing minutes of arc should be subtracted from the longitude of the Moon when the latitude and ayana (of the Moon) 8 are of like directions. In the contrary case, they should always be added to the longitude of the Moon. 3 The two corrections stated in the foregoing stanzas are known as dar- sana-safnskara or drkkarma {"visibility corrections"). The first correction, stated in stanzas 1-2, is known as aksa-drkkarma. 1 Cf. MBk, vi. 1-2U). 2 The Moon's ayana is north or south according as the Moon is in the half- orbit beginning with the tropical (sayana) sign Capricorn or in that beginning with the tropical (sayana) sign Cancer. 8 Cf. MBh, vi. 2(ii)-3.
