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

216 PAÑCASIDDHĀNTIKĀ IX.18
The angular diameters derived from the Original Saura (and the modern Sūrya
Siddhānta) are 32'.3 and 32'.0, respectively. Though the difference is small, we must investigate
why there is a difference at all. The error is about 160th part of itself in each case. Either the author
has taken values slightly different from those of the Original to derive the numbers here, or there
are some errors in the readings here.
Now for the readings. The first foot of the verse is in excess by one mātrā. There are eight digits
in the number, khakhavasu-khamunīndraviṣayāḥ, though there should be only six digits. So we have
corrected khakhavasukha into svaravasu following the form of the letters also. TS correct it as
khavasukha etc., giving seven places in the number, as 5147080. By this, the dividend has become
ten times what it actually is. Since they give the divisor, viz. the Sun's kakṣā, as one third of the actual,
(as seen already), they have made the angular diameter in minutes, thirty times the actual. Unaware
of the mistakes they have made they wonder why the angular diameter comes thirty times the
actual, and make the following curious comment: The correct angular diameters can be got only
by dividing what we get here by 30. But the author does not say anything about dividing by thirty.
Perhaps in his days there was the well-known understanding that what is got is to be divided by 30
to get the angular diameter. That is why, we surmise, the author has not instructed the division by
30 !! (vide page 50 of the Sanskrit commentary.) All this is the result of the errors in their correction
of the readings. NP too have sensed the error here and emend the expressions as khavasukha
munīnduviṣayāḥ (5,17,080), with the result that "the radius of the Sun is about four times the radius
of the earth, the radius of the Moon about one third" (pt. II, p. 73).
In the same way, there is one mātrā less in the second foot. Therefore, supplying the lost letter
we have read khakṛtartusuganāḥ as khakṛtartuvasuguṇāḥ. NP too, do the same. By this we get the five
places required in the dividend. But TS read it as khakṛtartusuraguṇāḥ, thus making the dividend
nine times what it is. They have already made the divisor, the moon's kakṣa, three tenths of what the
author has said it is. By this the angular diameter of the Moon also has been made thirty times the
real value, by them, again rousing their wonder in the manner mentioned before.
[मध्यज्या]
मध्यार्कलम्बिततिथेरन[क्ष]राश्युद्गमैः प्रतीपांशाः ।
प्राक् समलिप्ताहानिः क्रमेण पश्चाद्धनं कार्यम् ॥ १७ ॥
तन्मध्यविलग्नाख्यं तस्माच्चापक्रमांशकाः क्रमश: ।
तैरक्षवियुतयुक्तैर्या ज्या (म)ध्याभिधाना सा ॥ १८ ॥
Sin Zenith Distance of Meridian pt.
17. Find the interval between midday and the moment of new moon. If the
Sun is east of the meridian (i.e. if new moon falls in the forenoon), find the
degrees of right ascension corresponding to this time using the ascensional
differences of zero latitude, (laṅkodayamāna.), backwards from the Sun.
Subtract these degrees from the Sun (= Moon) of the moment of new moon.
If the Sun is west of the meridian, (i.e. if new moon is in the afternoon), find
the degrees corresponding to the interval counting forward from the Sun,
and add to Sun (= Moon).