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

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The concept of a month originally arose out of the
phenomenon of new-moons, for, this phenomenon alone
appeals to every lay man, when he could not sight the
Moon. The concept of an year arose originally out of
what is called a tropical year, which is the time between
two consecutive conjunctions of the Sun with an equi-
noctial point and which it is that makes the seasons recur.
Thus the primitive man must have had the concept of an
year when he once saw the mango trees blossoming and
again when he saw them blossom. This is why the Hindus
celebrate the new year's day with eating the neem flower
with unripe mangos, which goes by the phrase Nimba-
Kusuma bhakshanam or eating the neem flower. In the
Vedic times, however, the year began with the luni-Solar
month called Mārga-Śīrṣa, which brings in the new year
crops. In the Vedic sacrifices, there is thus what is called
the Āgrahāyaṇeṣṭi, where the word Āgra-hāyaṇa means
the Mārga-Śīrṣa month. The etymology of the word is
that अग्रे हायनं यस्य तत् आग्रहायणम् ie the year is ahead of this
month, which therefore is the beginning month of the year.
This is also why the ancient lexicon named Amarakośa
enumerates the months from Mārga-Śīrṣa. This is the
month when the full moon occurs when the Moon is in the
star Mṛgaśira. We have also an inkling from this that the
vernal equinoctial point was probably situated in the star
Mṛgaśira. The Veda however enumerates the stars from
the star Kritticā, and we have a statement in the Śata-
patha-Brāhmaṇa that "एता ह वै कृत्तिकाः प्राच्यै दिशो न श्च्यवन्ते
ie Behold ! these stars which go by the name the Krit-
ticas do not deflect from the east-point. As this group
of Krittikas is situated on the ecliptic, the statement that
they were rising in the east signifies that the Vernal equi-
noctial point was situated in the Kritticas". Arguing
about the situation of the vernal equinoctial point in the
so-called Vedic times, the late Lokamānya Bāla Gangā-
dhara Tilak concluded that Vedic literature must have had
its beginning about eight thousand years ago.
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