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

III. 14 III. PAULIŚA-SIDDHĀNTA 53 total phase can be observed well and therefore specially chosen by the Sūrya Siddhānta). In another place, say in Banaras, the beginning of the total phase is observed to be at nāḍikās 6-12, (of course by its own time, i.e. local time). The time difference for longitude must be patently the difference between the two times, i.e. nāḍīs 6-12 minus nāḍīs 5, i.e. nā. 1-12. As the local time must increase as we go east, we can also say that Banaras is east of Ujjain. [इष्टदेशास्तकालः] देशान्तरनाडीभ्य-श्चरनाड्यर्धं क्षयस्तु पूर्वार्द्धे । चक्रस्यार्धे चान्ये वृद्धिस्तद्भोगमपि जह्यात् ॥ १५ ॥ Local Sunset time 15. If the Sun is in the six rāśis Meṣa etc., subtract half the caravināḍis from the time difference for longitude. If the Sun is in the six rāśis Tulā etc. add half the cara-vināḍis to the time difference for longitude. Find the motion of the planet (the Sun or Moon, in this context) during this time. Subtract this from the longitude of the planet computed. (The planet for the beginning of the local day, i.e. for local sunset, is obtained). Example 7. The time difference for longitude at a place (in India) with reference to Yavanapura is 10 nāḍīs. The Sun is rā. 9-0-0 and the cara for that day at the place is 4 nāḍīs. The Moon computed is rā. 4-8-0 and its daily motion 840'. Find the Moon at the beginning of the local day, i.e. at local sunset of the place. Longitude time difference = 10 nāḍīs. Half cara = 4/2 = 2, nāḍīs. As the Sun is within the six rāśis from Tulā, adding 10 and 2, we get 12 nāḍīs. The motion per day is 840'. The motion for 12 nāḍīs is, 840' × 12/60 = 168' = 2° 48'. Subtracting from the computed Moon, the Moon at local sunset is, rā. 4-8-0 − 2° 48' = rā. 4-5-12. The explanation of the procedure is as follows: As the days from Epoch are from mean sunset at Yavanapura, the planets computed for the days from Epoch are for mean sunset at Yavanapura and if they are required for any time in the day, they have to be found by adding the motion during the time. Therefore if the planets are required for local sunset at any other place, the time interval between the local sunset and Yavanapura mean sunset has to be found first, and the motion for the interval applied to the planet computed. This motion is subtractive if local sunset is earlier, and additive if later. Now, the author intends the procedure for India alone, and at places in India the local sunset is always earlier than Yavanapura mean sunset. This is because nowhere in India (including Afghanistan) is the difference for longitude from Yavanapura less than 4¹/² nāḍis, and the half cara greater than this. Because India is east of Yavanapura in the local mean sunset is earlier by the time difference for longitude. The actual sunset is earlier than the mean sunset or later by half the cara-nāḍīs. It is later if the Sun is in the six rāśis, Meṣa etc., because the day-time is longer. It is earlier if the Sun is in the six rāśis, Tulā etc. Therefore the local actual sunset is earlier than Yavanapura mean sunset by the time difference for longitude minus half the nāḍīs of cara when the daytime is greater. But 15a. A. नाडीभ्य; B. नाडीम्य c. B. विक्रस्याद्वै b. C. नाड्यर्थक्षय०. B. पूर्वार्द्धम् d. B. वृक्षि. B. भोरामपि; D. भागमपि