VSS. 15-1 7(i)] CALCULATION OF THE MEAN LONGITUDE 5 Revolution-numbers of the planets, etc., 1 in a period of 43,20,000 solar years (called a yuga): 9-14. (In a. yuga) the revolution-number of the Sun has been stated to be ten thousand times 432 (i.e., 43,20,000); of the Moon, 5,77,53,336; of Mars, 22,96,824; of Jupiter, 3,64,224; of Saturn, 1,46,564; of Mercury and Venus, the same as that of the Sun; of the Moon's apogee {mandocca), 4,88,219; of {the sigh- rocca of) Mercury; 1,79,37,020; and of (the sighrocca of ) Venus, 70,22,388. The mean Sun is the sighrocca of the remaining pla- nets. The revolution-number of the Moon's ascending node {pata) is 2,32,226; and the number of civil days (in a vuea) 1,57,79,17,500. 2 K S ] The fighroccas of Mercury and Venus are imaginary bodies which are supposed to revolve around the Earth with heliocentric mean angular veloci- ties of Mercury and Venus respectively, their directions from the Earth always remaining the same as those of Mercury and Venus from the Sun. It will thus be seen that the revolutions of Mars, the sighrocca of Mercury', Jupiter, the fighrocca of Venus, and Saturn, given above, are equal to the revo- lutions of Mars, Mercury, Jupiter, Venus and Saturn respectively around the Sun. Tne mean longitudes of Mars, the fighrocca of Mercury, Jupiter, the sighrocca of Venus, and Saturn, which are obtained by the rule given below are therefore, equivalent to the heliocentric mean longitudes of Mars, Mer- cury, Jupiter, Venus, and Saturn respectively. A rule for calculating the mean longitudes of the planets for mean sunrise at Lanka : 15-17(i). Divide the product of the revolution-number ot a planet and the ahargana by the (number of) civil days (in a yuga); thus are obtained the (number of) revolutions (per- formed by that planet). From the (successive) remainders multi- plied respectively by 12, 30, and 60 and divided by the same divisor (viz. the number of civil days in a yuga) are obtained the signs, degrees, and minutes, etc. (of the mean longitude of that pl anet) for (mean) sunrise (at Lanka). 3 the EaTth. 1 h ' nUmbCr ° f rcvolutions that the P ,ancls > etc , make around a Gf. MBh, vii. 1-5, 8. 1 Cf. MBh, i. 8.
