Brihat Parashara Hora Shastra
स्वेष्टकालं पलीकृत्य तिथ्याप्तं भादिकं च यत्। चरागद्विभसंस्थेऽर्के भनौ युङ् नवमे सुते॥ ७२॥
If Sūrya is in a Fixed Rāśi, add 240 degrees additionally and, if in a Dual Rāśi, add 120 degrees in furtherance to get Pranapad.
english translation
sveSTakAlaM palIkRtya tithyAptaM bhAdikaM ca yat। carAgadvibhasaMsthe'rke bhanau yuG navame sute॥ 72॥
hk transliteration by Sanscript