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

XVII.9 XVII. SAURA: TRUE PLANETS 305 The fig, is for Mercury and Venus, having the Sun as the mean planet. For Mars, Jupiter and Saturn, interchange the planet and the Sun. The geocentric position in both cases is mean planet plus Q. If Q is formed below the horizontal line, it is so much negative and must be subtracted from the mean. Example 1. Find the true, i.e. geocentric, Mars at 1,20,553 days from epoch. Given: Mean Mars, already found with bīja corr. 8ʳ 9° 2′ Śīghra Mars = mean Sun of date = 0ʳ 17° 18′ Aphelion (apogee) of Mars assumed, 3ʳ 20° (for 120° given) Epicycle of apsis = 70°, Apsis of conj. = 234°. First step. Anomaly of conj. = Śīghra − mean = 17° 18′ − 8ʳ 9° 2′ = 128° 16′. This is more than 90° and less than 180°. So, subtracting from 180°, bhujāṃśa is 51° 44′, Koṭiaṃsa = 38° 16′ Bhuja = 94′ 2″. Koṭi = 74′ 17″ Bhuja-result = 94′ 2″ × 234° ÷ 360° = 61′ 14″ Koṭi-result = 74′ 17″ × 234° ÷ 360° = 48′ 17″ As anomaly of conj. is between 90° and 270°, this is subtractive from 120′. 120′ − 48′ 17″ = 71′ 43″. 120′ × bhuja-result ÷ √(71′ 43″² + _bhuja-result_²) = 120′ × 61′ 14″ ────────────────────── √(71′ 43″² + 61′ 14″²) = 77′ 55″. Arc for 77′ 55″ = 40° 30′ ½ arc = 20° 15′ Subtracting from aphelion (since anomaly of conj. is from 0° to 180°), 110° − 20° 15′ = 89° 5′, which is the half-corrected aphelion. Second step Anomaly of apsis = 249° 2′ − 89° 45′ = 150° 17′ This is more than 90° and less than 180°. So, Bhuja degrees = 20° 43′. Bhujā = 42′ 24″. Bhuja-result (i.e. eq. of the centre) = 42′ 24″ × 70°/360° = 8′ 15″ Arc for this = 3° 56′; ½ arc = 1° 58′ This is additive because An. of apsis is between 0° and 180°. Half rectified aphelion + 1° 58′ = 91° 43′ = full rectified aphelion. Third step The corrected anomaly of apsis = 249° 2′ − 91° 43′ = 157° 19′. The bhuja degrees = 22° 41′. Bhuja = 46′ 17″. The Bhuja-result = 46′ 17″ × 70°/360° = 9′ 0″ . Arc of 9′ 0″ = 4° 18′, deductive because an. of apsis is between 0° and 180°. Mean − arc = 249° 2′ − 4° 18′ = 244° 44′ = mean corrected (for eq. centre).