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

222 PAÑCASIDDHĀNTIKĀ IX.23 (iii) Nāḍis of parallax = the parallax in longitude found in (ii) × 60 ÷ the motion of the tithi per day. Subtracting the nāḍis from new moon in the forenoon, and adding in the afternoon, the p.c.n. is got. Finding the m.e.p. etc. of the p.c.n., the work should be repeated upto getting the nāḍis in (iii). These nāḍis are to be subtracted or added to the original new noon. A better p.c.n. is got. Using this time the work may be further repeated for a still better approximation. Example 15. To continue Ex. 10 In the last example the śaṅku got is 103′ 10″. In Ex. 10, the motion per day of the Sun and the Moon found are 57′ and 810″, the Sun's kakṣā found is 16,641 and the Moon's 1171.2. The square of the dṛk-kṣepa kept apart, is 792.25. From these: (i) Dṛggati = √(14,400 − (103 1/6)² − 792.25) = 54′ 27″. (ii) (a) Sine Sun's par. in long. = 18 × 54′ 27″ ÷ 16,641 = 3″.6. (b) Sine Moon's par. in long. = 18 × 54′ 27″ ÷ 1171.2 = 50″.2. The Sun's parallax is arc of 3″.6 = 1′.7. The Moon's parallax is arc of 50″.2 = 24′.0. The parallax in longitude = 24′.0 − 1′.7 = 22′.3. (iii) Nāḍis of par. = 22′.3 × 60 ÷ (810′ − 57′) = 1-47. Since new moon is afternoon, adding to the time of new moon, the p.c.n. = nā. 20-40 + nā. 1-47 = nā. 22-27. We shall repeat the operation for a better approximation. (The motions of the Sun and Moon per day, and their kakṣās need not be done again.) The nāḍis of the p.c.n. after midday = 22-27 − 15-40 = 6-47 = 407 vināḍis. The right ascension, corresponding to the interval of 407 vināḍis, using the ascensional differences of zero latitude = 10°

• 10° + 10° + 10° × 85.2 ÷ 108.8 (for vināḍis 105.4 + 107.6 + 108.8 + 85.2) = 37° 50′, after the Sun ( = rā. 2-0-2, 2′ more for the 2 nāḍis later). ∴ The m.e.p. = rā. 2-0-2 + rā. 1-7-50 = rā. 3-7-52. The declination of m.e.p. = 23° 46′ north. The zenith distance of the point = 23° 46′ − 10° 24′ = 13° 22′, north. Sine z.d. of m.e.p. = 27′ 44″. The o.e.p. at p.c.n. = rā. 6-8-48 (using as before the ascensional differences of 10° 24′). Since amplitude of the point = 7′ 34″. Sine (m.e.p. ~ n) = 27′ 44″ × 7′ 34″ ÷ 120 = 1′ 45″. Sine ² (z.d. of n) = (27′ 44″)² − (1′ 45″ )² = 765.89. Sine (z.d. of n) = 27′ 40″. Śaṅku = √(14,400 − 765.89) × sine (rā. 4-8-46) ÷ 120′ = 91′ 1″. Dṛggati = √(14,400 − (91′ 1″)² − 765.89) = 73′ 9″. Sine Sun's par. in long. = 18 × 73′ 9″ ÷ 16,641 = 4″.8. Parallax = 2′.2. Sine Moon's par. in long = 18 × 73′ 9″ ÷ 1171.2 = 1′ 7″.5. Parallax = 32′.2. Relative parallax = 30′.0. Nāḍis of parallax = 30′ × 60 ÷ 753′ = nā. 2-23. Adding to time of new moon, the closer p.c.n. = nā. 20-40 + nā. 2-23 = nā. 23-3.