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

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radius. This circle is called Kadamba-Bhrama-Vritta or
the circle in which the pole of the Ecliptic revolves round
P (due to diurnal revolution of the Earth). In that circle
Hsine of an angle will be H sin δ............Or again draw the
great circle with the planet's position as the pole, called
the horizon of the planet. The arc intercepted on this
circle between the Ecliptic and the celestial Equator will
be Āyana Valana and that intercepted between the celestial
Equator and the horizon is the Ākṣa Valana; and the
arc intercepted between the Ecliptic and the horizon is the
Sphuṭa Valana.
Or again draw a circle with K as centre and radius
ω = 24°. This circle is called the Jina-Vritta where the
word Jina means 24. Let a secondary to the Ecliptic
passing through K and K' the poles of the Ecliptic revolve
with KK' as fixed. When this revolving circle passes
through Cancer (Sāyana) it will be passing through P.
The angle turned through by this circle from Cancer, will
be equal to the angle turned through from P. The Hsine
of that angle in the Jina Vritta will be H sin δ of a
longitude equal to that angle. This is the Āyana Valana
and it arises at the end of Dyujyā, since the north-polar
distance of the planet is (90-δ) whose Hsine is Dyujya
ie. H cos δ. The corresponding Āyana Valana in a circle
of radius R is got by multiplying by R and divided by
H cos δ.
Let us clarify Bhāskara's mind. (Ref. fig. 81) Let
PBD be the Jina Vritta drawn on the sphere with K, the
pole of the Ecliptic as centre and ω=24° as radius. Let
a revolving secondary to the Ecliptic coincide initially
with KC where C is Cancer. Let it occupy subsequently
the position KM where M is the centre of the Moon's disc
taken to be on the Ecliptic as is the case very approxi-
mately at the moment of an eclipse. Now the Āyana
Valana is the angle KMP. Let MA be the declination of
M. Produce MP to L such that MK=ML=90°. Hence