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

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we have an approximation of the Mean planets. Treating
these as the Mean planets, again obtaining the Manda and
Śīghraphalas and again applying them inversely and
repeating the process till constant values are obtained, we
have by this method of successive approximation the Mean
planets required.
Comm. The method of successive approximation is
clear.
Verse 46. To obtain the equinoctial shadow.
Convert the Ayanāṁśas into minutes of arc, and
divide by the mean daily motion of the Sun; then we
have the number of days before the Meṣa or Tulā Saṁ-
krānti day, or before Makara and Karkaṭaka Saṁkrānts
days, when the Sun will be in equinoxes or Solstices
respectively. The mid-day shadow of the Sun cast by the
gnomon on such an equinoctial day, will give us the
equinoctial shadow required.
Comm. The palabhā or equinoctial
shadow as it is called is the length of
the shadow cast by a gnomon taken
to be of 12 units in length, (measuring
the shadow also in the same units), at
noon of an equinoctial day. In other
words, if this shadow be of s units,
clearly s / 12 = tan ϕ (Vide fig. 18).
The Ayanāṁśas are the degrees of
the arc of the ecliptic in between the
Hindu Zero point of the Zodiac and the
first point of Aries which is now behind the former due to
the phenomenon known as the precession of the equinoxes.
They are called Ayanāṁśas because the solstices are also
behind the Makara and Karkaṭaka Saṁkrānti points of
the Hindu Zodiac or points which have Hindu longitudes
270° and 90° resply, by the same arc. The Hindu astro-