Pancanga: The Almanac ||122||

1aGod Agni said: Time is (reckoned by) the accumulated number of years, (months etc, from the epoch up to the point of time under consideration). I shall set forth the calculation involved in reckoning time.
1bThe accumulated (i.e. elapsed) number of years (up to the required point of time) is to be multiplied by 12 (arka) and the (number of months elapsed in the current year from) Citra is to be added to the product).
2aThe sum obtained is doubled and placed at two places. To one is added 4 (veda) and to the other 865 (pahcangasta). (The latter figure is to be divided by 60 and the quotient added to the first, while the remainder is kept as the second figure). The resultant is to be called ‘guna’.
2b(The guna) is placed at three places (one below the other, in the serpentine fashion, each being written one step to the right of the preceding one). The ‘middle’ is multiplied by 8 (vasu) and the product again multiplied by 4 (veda). (The columns are to be added up.) and again written as ‘upper’ ‘middle’ and ‘lower’.
3Subtract 398 (asta-randhra-agni) from the lower and 87 (saika-rasastaka) from the ‘middle’. Divide (the ‘middle’ and the ‘lower’) by 60 and add the quotients to the preceding, (keeping the remainders in their places).
4aVara-tilhi correction. The first (i.e. ‘upper)’ when divided by 7 will give the week-day constant for tithi. (The quotient is to be rejected as of no more use.) The resultant is to be used as the Vara-correction for tithi-nadikas.
4b-5Maksatra-Toga constants. The ‘guna’ derived above is to be multiplied by 2, and 3 subtracted from the second figure. Guna is set down before the result (in the serpentine fashion). 30 (kha-rama) is set down below the last figure, and 6, 12 and 8 (rasa-arka-asta), respectively, below the three figures, (and the columns added up and elevated by dividing by 60). Divide the first figure by 28 and place it below the ‘correction for thiti’ (obtained in verse 4a). (add and take the result as a second ‘upper’).
6-8aThe ‘guna’ is halved, 3 subtracted (from its second figure) and the whole expression multiplied by 2. The first figure here is multiplied by 11 (rudra), the second figure is increased by 1 and divided by 39, the quotient being subtracted from the first figure and the remainder kept in its place. The resultant is termed madhya. Subtract 22 from the first figure and divide it by 60; the remainder is deductive; the quotient is added to the (second) ‘upper’ (of verses 4b-5). The first figure is divided by 27 and the remainder set down in its place. The resultant expres¬ sion is the constant for the correction of naksatra and yoga.
8b-9aNaksatra. For the calculation of tithi there is a monthly constant, being 2 pindas (i.e. whole units) and 32 nadikas (which has to be added to the tithi correction contained in verses 4a). Similarly, for the naksatra, there is a monthly constant, being 2 naksatras and 11 nadikas, (which, when added to the naksatra correction of verse 8a, will give the elapsed naksatra and the nadikas gone in the current naksatra .
9b-10Weekday and commencing point of Tithi. Add the tithi correction above (to the varadi-tithi correction got in verse 4a), placing the tithi number below the vara number. Divide by 7 (if vara plus tithi exceeds 7); the remainder will give the elapsed week-day counted from Sunday, and the nadikds gone in the next day at the point of the commencement of the relevant tithi) In the case of tithis after adding the complete units (pindakas) the sum should be divided by 14 (if the sum exceeds 14, and the remainder taken as the tithi .)
11-14aTrue-Tithi correction. The correction, in nadikds, for the fourteen tithis would be, in order, minus, plus, plus, minus, (minus and so on). Whi e the correction for the 14th tithi is zero), the correction for the thirteenth and the first is 5 (vindadikds) (each, minus and plus, respectively), that for the 12th and the 2nd, 10 (vinadikas), that for the 11th and 3rd, 15 (vinadikas), that for the 10th and 4th, 19 (vinadikas), that for the 9th and 5th, 22 (vinadikas), that for the 8th and the 6th, 24 (vinadikas), and that for the 7th, 25 (vinadikas). These khandakas (correction-bits) are to be applied appropriately to the pindakas (full units).
14b-17Vikala correction. In the case of (the three), Karkataka, (Simha and Kanya), divide the rasis, respectively, by 6 (ritu)y 4 (veda) and 3 (traya)] in the case of Tula, (Vriscika and Dhanus), divide, respectively, in the reverse, 3, 4 and 6; in the case of Makara, (Kumbha and Mina), respectively, by 3, 4 and 6; and in the case of Mesa, (Risabha and Mithuna), divide, respectively, in the reverse, i.e. by 6, 4 and 3. The correction, in vikalas, which is positive in the case of the three, Mesha etc., are 50 (kha-isu), 40 (kha-yuga) and 12 (mitra); in the case of the three, Karkataka etc., it is in the reverse order, (i.e. 12, 40 and 50, but positive); in the case of the three, Tula etc., (it is 50,40 and 12), negative i (and, in the case of the three, Makara etc., it is 12, 40 and 50, negative).
17b-19aApplication of the vikala correction. The vikala correction is to be applied to the tithi multiplied by 4. Multiply their eleven vikalas by the thr difference in liptas (i.e. kalas) between the elapsed and to-elapse portions of the tithi and divide by 60. If the elapsed portion is less than/the portion to-elapse, treat the correction as positive even if it be negative and or positive, retain it as positive; while, in the case of the portion to- elapse being greater, the reverse is the case (i.e. the correction is to be taken as negative both if it is negative or positive).
19b-21aFurther correction to the Tithi. Double (?Treble) (the nadikas of) the tithi and subtract from it one-sixth of (the product). Apply to it the tlthi-nadikas obtained for the sun in the reverse order and subtract the result from 60; the true nadis of the tithi would be obtained. If not subtractable, add 60 and subtract; if more than 60, reduce it by 60 and subtract .
21b-22Toga. The tithi is associated with the constellation The tithi multiplied by 4 and a third (of the tithi) added to it. Apply to it the negative correction. (By dividing it by 27, the yoga elapsed and the nadikas in the current yoga are obtained.) True tithi has be to be used as the means for calculating the yoga.
23aThe yoga is, indeed, got also by adding (the longitudes of) the sun and the moon (in kalas and dividing by 800) .
23b-24aKarana. (The number of) the tithi reduced by 1 and multiplied by 2, and the product divided by 7, gives the karana of daytime. The tithi-number multiplied by 2 and the product reduced by I and divided by 6 (krita) gives the karana of the night .
24b-cThe karana of the end (i.e. second half) of the 14th tithi of the dark fortnight is called Sakuni; (that of the first half of the full moon day is called Catuspada; that of the end (i.e. second half of the full moon day) is called Ahi (Naga); and that of the beginning (i.e. first half) of the prathama (of the bright fortnight) is called Kimstughna.