सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

PĀTĀDHYĀYA
Verse 1. Even scholars get confused while computing
the occurence of a Pāta, unable to know whether it has
already occurred or is going to occur. So, I seek to clarify
the method of computing the moment of occurrence of a
pāta.
Comm. (1) There are what are called pātās, two in
number, called Vyatipāta and Vaidhṛti. The first is
defined as occurring at that moment when the Sun and
Moon have equal declinations, being situated in opposite
Ayanas but the same goḷa. The words Uttaragoḷa and
Dakṣiṇagoḷa are used by Hindu Astronomers as the
northern and southern halves of the celestial sphere on
either side of the celestial equator, respectively; where as
the words Uttara-Ayana and Dakṣiṇa-Ayana are used to
connote the times when the Sun or Moon have tropical
longitudes (measured from r instead of Aswini, the zero
point of the Hindu Zodiac) one lying between Capricorn
and Cancer, and the other lying between Cancer and
Capricorn. Thus Vyatipāta occurs when the Sun and
Moon each lies in one of the first or second quadrants of
the ecliptic measured from r or each lies in one of the
third or fourth quadrants of the ecliptic; (both should not
lie in the same quadrant) and have equal declinations.
The second Pāta Vaidhṛti occurs when the Sun and
Moon have equal declinations, they being situated in the
same Ayana but opposite goḷas. These two moments are
considered to have malefic effects on humans and the world
of life. Though the moments are to be computed by a
knowledge of spherical astronomy, they have only an
astrological significance. A chapter, usually the last, has
been devoted to this subject in every book of Hindu
Astronomy. The method of computation was felt difficult
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