Surya Siddhanta
गतभोग्यासवः कार्या भास्कराद् इष्टकालिकात् । स्वोदयासुहता भुक्तभोग्या भक्ताः खवह्निभिः॥
From the given time in Práṇas (at the end of which the Horoscope is to be found) subtract the Bhogya time in Práṇas and the rising periods of the next signs (to that in which the Sun is, as long as you can, then at last, you will find the sign, the rising period of which being greater than the remainder you will not be able to subtract, and which is consequently called the aśuddha sign or the sign incapable of being subtracted, and its rising period the aśuddha rising). Multiply the remainder thus found by 30 and divide the product by the aśuddha rising period: add the quotient, in degrees, to the preceding signs (to the aśuddha sign) reckoned from Aries: (and to the sum apply the amount of the precession of the equinoxes by subtraction or addition according as it will be additive or subtractive); the result, (thus found), will be the place of the Horoscope[1] at the eastern horizon. [1. Thus there are two processes for finding the Horoscope, one when the given time is after sun-rise and the other when it is before sun-rise, and which are consequently called Krama or direct and Vyúlkrama or indirect processes respectively. B. D.]
english translation
gatabhogyAsavaH kAryA bhAskarAd iSTakAlikAt । svodayAsuhatA bhuktabhogyA bhaktAH khavahnibhiH॥
hk transliteration by Sanscript