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

234 PAÑCASIDDHĀNTIKĀ X.6
Moon's orbit M
R
r
Ecliptic S M'
Fig. X. 2
What has been proved for the lunar eclipse can be taken for the solar eclipse also, with the neces-
sary changes. The difference in motions should be here corrected for parallax and used. That this
corrected difference is always less than the uncorrected will be clear, when we consider that always
the parallax-corrected half duration is always greater than the uncorrected, which we have already
proved. Therefore it is clear that by multiplying the “corresponding minutes” by the uncorrected
half duration, and dividing by the parallax-corrected half duration, will give the parallax-corrected
“corresponding minutes”. It is also clear that in the case of the solar eclipse we must use in the proof
the parallax-corrected latitude in the place of the uncorrected latitude, the Sun for the Moon, and
the Moon for the Shadow. When this is done, the proof is exactly similar to that for the lunar
eclipse.
Another thing is to be noted. The Hindu astronomers took the amount of eclipse at full moon
or corrected new moon as the maximum and called it the magnitude, (grāsa-pramāṇa), though actually
this is only very nearly the maximum and the actual maximum occurs a little earlier or later. If we
take this full or new moon itself for doing the present work, since the time interval is zero, and
thereby the ‘corresponding minutes’ are also zero, the latitude itself becomes the distance between
the centres. Therefore we got that the amount eclipsed in this case (i.e. the magnitude) is to be got
by subtracting the latitude of full or corrected new moon, from the half sum of the angular diameters,
as already given.
Now for the readings: vāñcchitanāḍī (‘desired time’) is meant here the interval in time from the
full or new moon, either before or after. But TS have taken the expression to mean ‘the desired
point of time’, and in order to get the meaning of ‘interval’ that is wanted for use, have emended
the already correct sthitiliptāstābhyas tat into tatsthitiliptāvivarāt, which is unnecessary. Another
thing must be said here. If the reading had been tithiliptāḥ instead of sthitiliptāḥ given by the
manuscripts and accepted by us, it would have been better; for this would mean the minutes of tithi,
as indeed these are, being part of a tithi by nature.