Surya Siddhanta
नक्षत्रग्रहयोगेषु ग्रहास्तोदयसाधने। शृङ्गोन्नतौ तु चन्द्रस्य दृक्कर्मादाव् इदम् स्मृतम्॥
In calculating the conjunction (yoga) of a planet and an asterism (nakshatra), in determining the setting and rising of a planet, and in finding the elevation of the moon's cusps, this operation for apparent longitude (drkkarman) is first prescribed.
english translation
nakSatragrahayogeSu grahAstodayasAdhane। zRGgonnatau tu candrasya dRkkarmAdAv idam smRtam॥
hk transliteration by Sanscript