MEAN LONGITUDE WITHOUT AHARGANA Therefore, we have intercalary months in a yuga = Moon's revolution-number 13 (Sun's revolution-number), giving Moon's revolution-number = intercalary months in a yuga +-13 (Sun's revolution-number). Multiplying the two sides of this equation by the ahargana and dividing by the number of civil days in a yuga, we get mean longitude of the Moon (intercalary months a yuga) × (ahargana) revolutions civil days in a yuga + 13 (Sun's mean longitude). And rearranging this equation, we have mean longitude of the Sun - (1/13) 9 (intercalary months in a yuga) x ahargana civil days in a yuga { mean longitude of the Moon revolutions (1) (2) A rule for calculating the mean longitudes of the Sun and the Moon without making use of the ahargana: 13-19. For one (desirous of) calculating the mean longitudes of the Moon and the Sun without the use of the ahargana, the following method is stated: Reduce the years (elapsed since the beginning of Kaliyuga) to months, and add to them the elapsed months (of the current year). Then multiply that (sum) by 30, and add the product to the number of (lunar) days elapsed since the beginning of the current month. Multiply that (sum) by the number of intercalary months (in a yuga) and divide by the number of solar months in a yuga reduced to days: the quotient denotes the number of intercalary months (elapsed). Delete (or rub out) the divisor
