Surya Siddhanta
व्यस्ता व्यस्तैर् युताः स्वैः स्वैः कर्कटाद्यास् ततस् त्रयः। उत्क्रमेण षडेवैते भवन्तीष्टास् तुलादयः॥
From the Sun's longitude ascertained at the given time, find the Bhukta and Bhogya times in Práṇas, (in the following manner. Find the sign in which the Sun is and find the Bhukta degrees or the degrees which the Sun has passed and the Bhogya degrees or those which he has to pass). Multiply the numbers of the Bhukta and Bhogya degrees (separately) by the rising period of the said sign (at the given place) and divide the products by 30. (The first quotient is the Bhukta time in Práṇas in which the Sun has passed the Bhukta degrees, and the latter is the Bhogya time in Práṇas in which he has to pass the Bhogya degrees.)
english translation
vyastA vyastair yutAH svaiH svaiH karkaTAdyAs tatas trayaH। utkrameNa SaDevaite bhavantISTAs tulAdayaH॥
hk transliteration by Sanscript