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

176 PAÑCASIDDHĀNTIKĀ VII.4 Parallax in latitude 2. Multiply the degrees of latitude by 5 and divide by 27. Add or subtract the resulting degrees, respectively, to Rāhu's head or from Rāhu's tail, where the Moon is situated. (i) 3. Add three rāśis to the Moon, and find its declination in degrees. This multiplied by the nāḍīs of parallax (given by verse 1) and divided by 18, are to be added to the Head if it is forenoon and Uttarāyaṇa (i.e. the Sun is in its northward course), or afternoon and Dakṣiṇāyana. The degrees are to be sub- tracted from the Head if it is forenoon and Dakṣiṇāyana or afternoon and Uttarāyaṇa. For the Tail, the addition and subtraction should be inter- changed. (ii) 4. Take nāḍīs from sunrise to new moon if forenoon, the nāḍīs from new moon to sunset if afternoon. Multiply these by the degrees of the Moon's declination and divide by 80. The resulting degrees are to be added to the Head if the Moon's longitude is between 6 and 12 rāśis, and subtracted if bet- ween 0 and 6 rāśis. For the Tail, interchange the addition and subtraction. (iii) The corrections are: i. Ø° × 5 ÷ 27 ii. 'Degrees' × the nāḍīs of verse 1 ÷ 18, where 'Degrees' are to be got from sin 'degrees' = sin w sin (Moon + 90°)/120 iii. Degrees of Moon's declination × the time in nāḍīs from sunrise to (parallax corrected) new moon, or to sunset from parallax corrected new moon ÷ 80. The addition or subtraction is as instructed in the translation above. These rules follow from the formula derived already for parallax correction in latitude: p-lat = 49' sin z.d. N/120. 49' sin z.d. N/120 = sin w. cos Ø sin (AQ)/120³ − cos w. sin Ø/120², (from the two rt. △ s. Z NA and Z QA) = (i) − 49' cos w, sin Ø/120² + (ii) − 49' sin w cos Ø sin (Moon + 90°) × sin h. sec δ/120³ + (iii)

• 49' cos w. cos Ø tan δ. cos h/120³, (h being the hour angle of the Moon at parallax-corrected new moon). 2a. A.B1. पञ्चघ्नलि०. D. यमाप्ता b. B1. दक्षन्; D. [क्षेपे] क्षे मुख . A. पुच्छयोः; B1.2. पृष्ठयोः c. A. यक्षाधनं A.B. धनर्णं तन्न |; D. धनर्णः d. A. om दिग्; B1. दृग्गुणं; B3. दृगुड्गुणं; C.D. om दिग् c. A.B.C. राशिचरणा०; D. तद्राशिचरणा०; A. पुछे; B. पृष्ठे A.B.C.D. ०यनगुणं 4a. B. शेषं d. A.B.C. धनमृणनाड्यो (B1.3. ०ताड्यो). b. A.C.D. चन्द्रायन; B. चन्द्रानयन A. त्रशीति; A.B.C.D. दिक्० B. श्काशीति B. विभक्ता B1. ऋताः; B2.3. क्षताः 3a. B. धनं मृणं c. A.B. शेष. D. तुलाघ्णं घनं b. A. दिणे; B. दक्षिणं d. B. विपरीतं. A.B. पुछे