Brihat Parashara Hora Shastra
चेष्टोच्चरश्मियोगार्धं शुभरश्मिः प्रकीर्त्यते । अष्टभ्यश्च विशुद्धोऽसाबशुभाख्यश्च कथ्यते ॥ ५॥
Benefic and Malefic Rays. Add the Uchch Rasmis and Chesht Rasmis together and divide by two. The result will be auspicious rays (Subh Rasmis). Deduct from 8 the Subh Rasmis to obtain inauspicious rays (Asubh Rasmis).
english translation
ceSToccarazmiyogArdhaM zubharazmiH prakIrtyate । aSTabhyazca vizuddho'sAbazubhAkhyazca kathyate ॥ 5॥
hk transliteration by Sanscript