पञ्चसिद्धान्तिका (आचार्य वराहमिहिर - सूर्य, रोमक, पौलिश, वासिष्ठ एवं पितामह सिद्धान्त)

56 PAÑCASIDDHĀNTIKĀ III. 17 [रविमुक्तिः] ‘[यम]-शिखि-गुणा-ऽग्नि-यम-शशि’-‘वियुता सैका सरूप रूपै-का’ ‘खै’-‘क’वियुता च भानोः षष्टिर्भुक्तिः क्रमादेवम् ॥ १७ ॥ Sun’s daily motion 17. The daily motion of the Sun in minutes during each of the twelve months, Meṣa etc. is 58, 57, 57, 57, 58, 59, 61, 61, 61, 61, 60, 59. The daily motion for the month is found thus: During every solar month, the Sun moves one rāśi, i.e. 1800′. Dividing this by the days of the month the daily motion is got. Or, according to the length of the month, take 31, 30 or 29 days of the month, almost covering it. Find the motion for these days and divide by the number of days taken, the daily motion for the month is got. Because the daily motion thus found is very near sixty minutes, the author enumerates their difference from sixty, for the sake of convenience. The mean daily motion is 59′ 8″, which can be got dividing the minutes in 12 rāśis, i.e. 21,600, by the days in the solar year. Because the higher apsis, i.e. the apogee of the Sun, is about the middle of Mithuna, the Sun’s motion in Vṛṣhabha, Mithuna and Karkaṭaka is very slow, and the daily motion, 57′ given for these is proper. Because the lower apsis, i.e. the perigee, is about the middle of Dhanus, the Sun’s motion in Vṛścika, Dhanus and Makara is very quick, and the daily motion, 61′ given for these is proper. We shall here derive the motion for Meṣa and Tulā. Let us begin with the moment on the first day of Meṣa, when the mean Sun is zero. By III. 1, the kendram is 20° and the correction for making the Sun true is − 11′ × 20°/30° = − 7′. The true Sun is 0°−7′ = rā. 11−29−53. 31 days after this moment, the mean Sun is, 31 × 120 ÷ 43831 × 360° = 30° 33′. The kendram is 30° 33′ + 20° = 50° 33′. The true Sun is 30° 33′ − 11′ − 48′ × 20° 33′/30 = rā. 0-29-49. The motion of the Sun for 31 days is Rā. 0-29-49 − rā. 11-29-53 = rā. 0-29-56. The motion per day is 29° 56′/31 = 1736′/31 = 58′. Therefore 58′ is the correct motion for Meṣa and not what is mentioned in the given verse, and that is why we have suggested the emendation yama for guṇa in the text. We shall examine the daily motion for the Tulā. We shall begin work from the first day of Tulā when the mean Sun is 185°. The kendram for that is 185° + 20° = 205°. The true Sun is 185° − 11′ − 48′ − 69′ −70′ − 54′ − 25′ + 10′ × 25°/30° = 180° 31′ . Now we shall take a time 30 days later. The mean Sun then is 185° + 30 × 120 × 360°/43831 = 214° 34′. The kendram is 214° 34′ + 20° = 234° 34′ . The true Sun is 214° 34′ − 11′ − 48′ − 69′ − 70′ − 54′ − 48′ − 25′ + 10′ + 48′ × 24° 34′/30° = 210° 46′. The motion for 30 days is 210° 46′ − 180° 31′ = 30° 15′. The motion per day is 30° 15′ ÷ 30 = 60½′. The author gives this as a whole number, 61′; so it is all right. 17a. A.B.C.D. गुण c. C. भानां b. B. वियुक्ता d. C. क्रमाद् [भानोः] A.C. खैकै for सैका