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

IX.26 IX. SAURA-SIDDHĀNTA — SOLAR ECLIPSE 225
The maximum latitude is given in verse 6 to be 270'. The use of sine (Moon − Rāhu) has been
already indicated in the context of the Romaka, and therefore only indicated here. In correcting,
like directions are additive, and unlike directions subtractive, the resulting direction being that of
the greater. The parallax-corrected latitude is to be got for each of the time of first contact, last con-
tact, and middle, the last serving for immersion and emergence too, as these times are near enough
to the middle. The separate computation of the corrected latitude suggests that the nāḍīs of parallax
also are to be computed separately for the different times. Thus, the following is to be done:
(i) The uncorrected latitude = 270' × sine (Moon − Rāhu) ÷ 120 = sine (Moon − Rāhu) × 9 ÷
4. (If Moon − Rāhu) is less than 6 rāśis, the latitude is north, otherwise south. Rāhu here means the
Head of Rāhu).
(ii) Parallax-corrected latitude = latitude ± relative parallax in latitude (+ if of the same direc-
tion, and ~ if of different directions, the resulting direction being that of the greater).
Example 17. (To continue Ex.10,) find the parallax-corrected latitude at the final parallax corrected new
moon, i.e. at nāḍī 23-20.
This time is nāḍīs 2-40 later than new moon. So, from the data given in Ex. 10, Rāhu-head = rā.
7-29-24, and Moon = rā. 2-0-0 + 810' × 2 2/3 ÷ 60 = rā. 2-0-36. Moon − Rāhu = rā. 6-1-12. From
this,
Moon's latitude = 9 × sine (rā. 6-1-12) ÷ 4 = 5'.7, south. (∵ Moon − Rāhu-head) > rā. 6-0-0.)
(ii) Parallax corrected lat. = 5'.7 ~ 11'.2 = 5'.5, north (∵ of different directions, north being
greater.)
These rules have been explained before.
[विमर्दकालः]
अवनतिवर्गं जह्याद् रवीन्दुपरिमाणयोगदलवर्गात् ।
तन्मूला(त्तु) द्विगुणात्(ति)थिभुक्तवदादिशेत् कालम् ॥ २६ ॥
Duration of the eclipse
26. Subtract the square of the parallax - corrected latitude from the square of
the sum of the semi-diameters of the Sun and the Moon and find the square
root. Double this, and find the time for it, treating it as the motion of tithi.
(The duration of the eclipse it got.)
This verse has already occurred as verse 16 of chap. VIII and fully explained there. The only
difference is two mis-readings here.
Example 18. To continue Ex. 10.
In Ex. 11, the angular diameter of the Sun has been found to be 31', and of the Moon, 33' and
the daily motion of the tithi 753'. The parallax-corrected lat. has been found to be 5'.5. From these,
Duration in nāḍikās = 2 × 60 × √(31 + 33)/2 − 5.5² ÷ 753 = 2 × 60 × 31.52 ÷ 753 = *nā.*5-1.
26b. B3. ॰न्दुः. B. परिपरिमाणग्दल (B3. ॰योगदल) c. A.B. मूलात् d. A.B1.2.तिथिभुक्ति. B. ॰वदादिकेत्कालं