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

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even by a lay man during the course of a single night. So,
the period of a single sidereal revolution, could be roughly
recognized by noticing the conjunction of the Moon with
a luminous star. Having thus observed a good number of
sidereal revolutions, which could be done even with the
naked eye, the average period could be arrived at with
sufficient accuracy within the course of a few years.
Having thus obtained almost accurately the average of a
sidereal revolution of the Moon, the sidereal revolution of
the Sun could have been arrived at as follows. The
moment of an eclipse solar or lunar could be observed with
the naked eye.-Observing a good number of eclipses within
the course of a few years, the average of a lunation could
be easily arrived at very accurately, for, in between the
eclipses of the same nature an integral number of lunations
elapse. That the Sun also has a motion among stars must
have been noticed clearly during the course of a few
months, for, observing at Sunset the star that was rising,
it should have been noticed gradually even during the
course of a month, that the Sun must have been approach-
ing the star or vice versa and as the stars were found to
keep the distances amongst them constant, it was the Sun
that was approaching the star and not the star it was that
was approaching the Sun. Having decided thus that the
Sun was moving among stars from west to East, the
approximate period that the Sun took to complete a side-
real revolution was arrived at. Then, as both the Sun and
the Moon were having east ward motion, and as the Moon
has a more rapid motion, the arc by which the Moon over-
takes the Sun during a day was roughly noticed. Thus
arriving at a rough estimate of a lunation within which
a conjunction of the Moon with the Sun recurs, it was
noticed that the excess of the sidereal revolutions of the
Moon over those of the Sun gave the number of lunations.
Since a correct estimate of both a sidereal revolution of the
Moon as well as that of a lunation were previously arrived
at, the number of sidereal revolutions of the Sun during