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

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heliacally in the east. This phenomenon has been long
in the notice of even the most illiterate people of India
from times immemorial, as they were used to get up from
beds round about the time when a brilliant star rose
heliacally and stood in the eastern horizon, shining for a
good length of time before Sun-rise. Each star of first
magnitude thus played the part of a morning star for some
time, though perhaps the illiterate folk mistake them to
be the same star. Especially the brightest stars of the
zodiac thus play the part of morning and evening stars.
The case with respect to Agastya and Lubdhaka is different
in that even though they are far away from the zodiac,
yet they were noticed to be morning and evening stars by
virtue of their being of the first magnitude at a spot of the
sky in the vicinity of which no other such brilliant stars
are there. This is the reason why panchangā—Computers
have been in the habit of recording in the panchangā even
to-date the heliacal rising and setting of Agastya, also
because the heliacal rising of this star synchronized with
the setting in of S'arat-kāla or autumn. Since in India
the lunar Kārtica Ekādasi, ie. the 11th day of the bright
half of the lunar month roughly synchronized with 15th
Nov., when the Sun rose far in the south of the horizon,
this Agastya, though it be in the far south, happens to
play the part of a morning star and about the day when
it rose heliacally, there were no more rains and waters of
the rivers stood crystal-clear as described by many a
Sanskrit poet like Kālidāsa (vide the famous verse of
Kālidāsa प्रसादोदयादम्भः कुम्भयोने र्महौजसः 4th canto Raghu-
vams'a).
The star Lubdhaka or Sirius, the dog-star as it is called
in English parlance also was conspicuous as a morning
and evening star, whose heliacal rising was noticed and
recorded by English poets like Shakespeare and Milton.
Since one nādi corresponds to 6°, two nādis correspond
to 12°, degrees, which are spoken as Kālāṁs'as for the