20 MEAN LONGITUDE OF A PLANET 27-28. Multiply the number of years (elapsed since the beginning of Kaliyuga) by 149 and then divide by 576: the quotient is in terms of days. Add these days to ten times the number of years (elapsed): thus are obtained the so called ravija days. To the ravija days add the (residual mean) omitted lunar days obtained above (in stanza 23). From the sum subtract the (complete mean) intercalary months (obtained in stanza 22) as multiplied by 30. Whatever is obtained as the remainder is "the subtractive" for the (current) year. When the subtra- hend is greater, then the difference is prescribed as "the additive". Let Y denote the number of years elapsed since the beginning of Kaliyuga. The number of mean civil days in one mean solar year 365 + 149/576. Therefore, the number of mean civil days in Y mean solar years 365Y+ (149/576)Y 365Y+ residual mean civil days. = = = The number of mean omitted lunar days in Y mean solar years (5+29/36 + 43/72000) Y ==5Y+ residual mean omitted lunar days. (2) Adding (1) and (2), the number of mean lunar days in Y mean solar years (1) 370Y+ residual mean civil days + residual mean omitted lunar days. (3) From (3) subtracting 360Y (į. e., the number of mean solar days in Y years), the number of mean intercalary days in Y solar years 10Y+ residual mean civil days + residual mean omitted lunar days. (4) Subtracting the complete mean intercalary months (elapsed since the beginning of Kaliyuga as reduced to days) from(4),we get the residual mean intercalary days. These are equal to the mean lunar days lying between the
