Surya Siddhanta
शेषम् चेत् त्रिम्शताभ्यस्तम् अशुद्धेन विभाजितम् । भागैर् युक्तम् च हीनम् च तल्लग्नम् क्षितिजे तदा॥(C भागहीनम् च युक्तम् च)
From the time, in ghaṭikas, from noon, before or after, the Sun's place found at the given time, and the rising periods of the signs ascertained for the equator, find the arc, in signs, degrees, &c, (intercepted between the Sun and the meridian at the given place) subtract or add the signs &c. (just found) from or to the Sun's place (according as the given time is before or after noon); the result will be the place of the culminating point of the ecliptic (at the given time).
english translation
zeSam cet trimzatAbhyastam azuddhena vibhAjitam । bhAgair yuktam ca hInam ca tallagnam kSitije tadA॥(C bhAgahInam ca yuktam ca)
hk transliteration by Sanscript