Nilakantha's Annual Astrology

One Solar YearSauravarsha: the time it takes for the Sun to return to the exact same longitudinal position in the zodiac is completed when the Sun returns to the same zodiacal sign and degree it occupied at the moment of birth. The exact time when the Sun reaches those precise coordinates is the moment of the Yearly EntranceVarshapravesha: the commencement of the new astrological year for an individual. Based on Civil DaysSavana: a day measured from sunrise to sunrise, the Sun returns to that same position in 365 days, 15 Ghatis, 31 Palas, and 30 VipalasTraditional Indian units of time: 1 Ghati = 24 minutes; 1 Pala = 24 seconds; 1 Vipala = 0.4 seconds. This value is fixed as the ConstantKshepaka. By multiplying this constant across the four units of time by the number of Elapsed YearsGatavarsha and carrying over the full units to the next higher denomination, the total civil time elapsed for that age is found.

For example: Multiply 1, 15, 31, and 30 by 37 elapsed years. This results in 37, 555, 1147, and 1110. By dividing these by the standard 60 (for Ghatis, Palas, and Vipalas), we find that 37 years, 46 days, 34 Ghatis, 25 Palas, and 30 Vipalas have passed in civil time. This method should be understood for all such calculations. By adding the weekday of birth to these 46 days (and subsequent units), the specific weekday and time of the Yearly Entrance is determined. || 16 ||

original: "शिवघ्नोऽब्द: स्वखाद्रींदुलवाढ्य: स्वाग्निशेषितः ॥ जन्मतिथ्यन्वितस्तत्र तिथ्यावब्दप्रवेशनम् ॥ १७ ॥"

Once the weekday of the Yearly Entrance is known by the previous method, the following process is used to find the specific Lunar DayTithi on which this entrance occurs: Multiply the elapsed years by 11. Place this result in two positions. In the first position, divide by 170 and add the resulting quotient to the second position. Then, divide that total by 30. To the remainder, add the birth lunar day (counting from the first day of the bright fortnight). This gives the lunar day of the Yearly Entrance.

Example: Multiply 37 elapsed years by 11 to get 407. Place this in two spots. Divide 407 by 170 to get a quotient of 2. Add this 2 to the other 407 to get 409. Add the birth lunar day (9th) to get 418. Divide by 30; the remainder is 28. This indicates the Yearly Entrance occurs on the 28th lunar day, which is the 13th day of the dark fortnight Krishna Trayodashi.

In this calculation, the lunar day might occasionally shift by one day forward or backward. The correct day is the one where the calculated weekday matches either the day before, the day after, or the calculated lunar day itself. Here, the weekday is the primary factor; the lunar day is used to confirm which specific occurrence of that weekday within the month is the correct one, as a weekday repeats 4 or 5 times a month. In this example, the 28th lunar day was found, and the Yearly Entrance occurred on Saturday, the 12th lunar day...