Surya Siddhanta
याम्यक्रान्तौ विपर्यस्ते द्विगुणे तु दिनक्षपे । विक्षेपयुक्तोनितया क्रान्त्या भानाम् अपि स्वके ॥
But when the planet's declination is south, the reverse of this takes place (i. e. the results, just found, will be tbe lengths of the half night and half day of the planet respectively). (In both cases,) twice the results are the lengths of the day and night (respectively). In the same way, the lengths of the day and night of any fixed star can be determined from its declination which is to be found by adding or subtracting its latitude to or from the declination (of its corresponding point in the ecliptic).
english translation
yAmyakrAntau viparyaste dviguNe tu dinakSape । vikSepayuktonitayA krAntyA bhAnAm api svake ॥
hk transliteration by Sanscript