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

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as given by Hindu astronomy tally with the heliocentric
sidereal periods given by modern astronomy. This is also
one of the reasons why heliocentric motion of the planets
could not be detected by Hindu astronomy, and also why a
statement was made that "In the case of Mercury and
Venus the Sun was the planet. and they are termed as
S'īghrōcchas, whereas in the case of Mars, Jupiter and
Saturn, they are the planets while the Sun plays the part
of S'īghrōccha "कुजजीवशनीनां तु रविः शीघ्रोच्चनामकः, ज्ञशुक्रयोः
ग्रहः सूर्योभवेत्, तौ शीघ्रनामकौ" (An elucidation of this state-
ment will be given shortly)
In the case of the planets Mercury and Venus (Inferior
planets) one may wonder how under the geocentric theory,
their heliocentric periods could be arrived at, though they
were not recognized as such but were pronounced as the
"geocentric periods (not considered as heliocentric)" of
two points known as their S'īghrōcchas. Here we come
across the peculiar concept of a S'īghrōccha which arose
out of the fact of postulating a geocentric system in the
place of the heliocentric. This concept is to be elaborated,
in as much as confusion is there in the minds of many
interpreters of Hindu astronomy in this behalf.
In the first place let us consider as to how the rectifi-
cation of the Sun and the Moon, known as sphutikaraṇa
was achieved. Having got their sidereal periods, their
mean daily motions were calculated. Also a period was
conceived, during which this Sun and the Moon would per-
form an integral number of revolutions. This period was
termed as a Mahāyuga (or simply a yuga as we hereafter
name it) whose duration was estimated as 4320000 solar
years. That the yuga is an integral L.C.M. so to say of
the sidereal periods of the Sun and the Moon (also of the
other planets as we shall see shortly) could be seen from
the statement of the Surya Siddhānta युगे सूर्यज्ञशुक्राणां