Surya Siddhanta
स्थिरीकृतार्धरात्रेन्द्वोर् द्वयोर् विवरलिप्तिकाः। षष्टिघ्न्यश् चन्द्रभुक्त्याप्ताः पातकालस्य नाडिकाः॥
The minutes of interval between the moon's longitude as finally established and that at midnight give, when multiplied by sixty and divided by the moon's daily motion, the time of the aspect, in nadis.
english translation