2 MEAN LONGITUDES OF THE PLANETS [CH. I mencement of Caitra. Set down (the result thus obtained) at (two) separate places; multiply (one) by (the number of) in- tercalary months in a juga, which are 15,93,336 in zyuga ; and divide (the product) by 5184 into 10,000 (i.e., by 5, 18,40,000). Add the (resulting complete) intercalary months to the result placed at the other place. Then multiply (that sum) by 30 and (to the product) add the (lunar) days (i.e., tithis) expired (of the cur- rent month). Set down (the result thus obtained) in two places; multiply (one) by the (number of ) omitted lunar days in ayuga, i.e., by 2,50,82,580, and divide by 1,60,30,00,080. The result- ing (complete) omitted lunar days when subtracted from the result put at the other place give the (required) ahargana. The remainder obtained on dividing (the ahargana) by 7 gives the day beginning with Friday at sunrise (at Lanka). 1 • The above rule tells us how to calculate the ahargana, i.e., the number of mean civil days elapsed at mean suniise at Lahk^. 2 on a given lunar day (titki), since the beginning ofKaliyuga. The beginning ofKaliyuga, which is taken as the starting point of the reckoning of ahargana in the above rule, occurred on Friday, February 18, B.C. 3102, at mean sunrise at Lanka, when the Sun, Moon, and the planets are supposed to have been in conjunction at the first point of the naksatra Asvini (which is a fixed point situated near the star ^-Piscium). The duration of Kaliyuga, according to Aryabhata I, is 10,80,000 solar years. Four times this (i.e., 43,20,000 solar years) is the dura- tion of a bigger period called pjyuga (or maha-yuga). The following table gives the number of lunar months, solar months, intercalary months (i.e., lunar months minus solar months), lunar days, civil days, and omitted lunar days (i.e., lunar days minus civil days) in ayuga : 1 Cf. MBh, i. 4-6; vii. 6-7. 2 Lanka is a hypothetical place on the equator where the meridian of Ujjain (long 75°52' E from Greenwich) intersects it. Months and Days in a Tuga Lunar months Solar months Intercalary months Lunar days Civil days Omitted lunar days 1,60,30,00,080 1,57,79,17,500 2,50,82,580 5,34,33,336 5,18,40,000 15,93,336
