Surya Siddhanta
तद्दोस् त्रिघ्ना दशाप्ताम्शा विज्ञेया अयनाभिधाः ॥ ३-१०ख तत्सम्स्कृताद् ग्रहात् क्रान्तिच्छायाचरदलादिकम् ॥
(Rejecting the revolutions), find the Bhuja of the rest (i. e. signs, degrees &c. as mentioned in S'loka 30th of the 2nd Chapter). The Bhuja (just found) multiplied by 3 and divided by 10[1] gives the degrees &c. called the Ayana (this is the same with the amount[2] of the precession of the equinoxes). or a b × h 12 R = the Equinoctial shadow 12 {\displaystyle ab\times {\frac {h}{12R}}={\frac {\text{the Equinoctial shadow}}{12}}}; ∴ a b × h R {\displaystyle ab\times {\frac {h}{R}}} or the reduced Śankutala = the Equinoctial shadow; ∴ The reduced sine of amplitude = the Equinoctial shadow ± the reduced Bhuja; this explains the 7th Śloka. B. D. 1. 27° : 90°. B. D. 2. This is the distance of the Stellar Aries from the vernal equinox. B. D. Add or subtract the amount of the precession of the equinoxes (according as the asterisms are moving eastward or westward at the given time) to or from the place of a planet: from the result (which is equivalent to the longitude of the planet) find the declination, the shadow of the Gnomon, the the ascensional difference &c. This motion of the asterisms (or the precession of the equinoxes) will be verified by the actual observation of the Sun when he is at the equinoctial or the solstitial points.
english translation
taddos trighnA dazAptAmzA vijJeyA ayanAbhidhAH ॥ 3-10kha tatsamskRtAd grahAt krAnticchAyAcaradalAdikam ॥
hk transliteration by Sanscript