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

Chapter Seven (PAULIŚA-SIDDHĀNTA) – SOLAR ECLIPSE ७. सप्तमोऽध्यायः पौलिशसिद्धान्तः — रविग्रहणम् Introductory This chapter deals mainly with the solar eclipse according to the Pauliśa. But the last two verses giving the computation of the solar eclipse gives the lunar eclipse also. It is from this that we have to conclude that the lunar eclipse of Chap VI is that of the Vāsiṣṭha. The method of the Pauliśa for correcting the Moon’s latitude for parallax is peculiar. The correction is done on Rāhu, and thence carried to the latitude. Also, this is the earliest siddhānta to deal with the solar eclipse, and thus, with its peculiar method, historically important. [लम्बनम्] दिनमध्यमसंप्रा(प्या) यावत्यो नाडिका व्यतीता वा | ताभ्यः षड्गुणिताभ्यो ज्यात्रिंशांशस्तिथे(नामः) || १ || Parallax of longitude

1. Find the interval between mid-day and the time of new moon, in nāḍīs. Multiply this by 6. Degrees are got. Find its sine. Divide it by 30. The result is the parallax in nāḍīs to be deducted from the time of new moon if new moon is before mid-day, and to be added to the time of new moon, if after mid-day. The new moon corrected for parallax in longitude is obtained. Thus: i. nāḍīs of parallax = sine (interval in nāḍīs between mid-day and new moon × 6) ÷ 30. ii. Parallax corrected new moon = new moon ∓(i), minus for forenoon, and plus for afternoon. The rationale of parallax correction is as follows: A lunar or solar eclipse occurs when the Moon gets so close to the earth’s shadow or the Sun, that it enters the Shadow so as to be darkened by it, or hides the Sun from the observer’s view. Now, the Moon being darkened by the Shadow is practi- cally independent of the position of the observer on the earth. But the Moon hiding the Sun depends upon the observer’s position, owing to parallax. So parallax correction has to be done in the solar eclipse. The critical angular distance is the sum of the semi-diameters. The angular dis- tance between the Sun and the Moon is calculated from the longitudes of both and the latitude of 1a. A.B.C.D. संप्राप्ता c. B. गुणितान्यो b. B1.2. यावन्त्यो A. व्यतीता वत; B. व्यतीता वत्त | d. A.B. ज्यास्त्रिंशांशः A.B. तीथिनाम; C. तिथेर्नाम