Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 1 · Basics and Panchanga
ज्योतिषमूलं पञ्चाङ्गं च
स्वाधोधः प्रविशोध्याथ मेषाल्लंकोदयासवः ।स्वागाष्टयोथंगोगैकाः शरत्र्येकं हिमांशवः ॥ १४६ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 54, verse 146.
Subtract each from the one below it. These are the rising asus (4-second units) at Lanka, from Aries: 1670, 1795 and 1935.
Simple meaning: At the equator Aries rises in 1670 asus, Taurus in 1795, Gemini in 1935.
स्वदेशचरखंडोना भवंतीष्टोदयासवः ।
Take off the latitude parts to get local rising times. Cancer, Leo and Virgo add them back in reverse.
उत्क्रमेण षडेवैते भवंतीष्टास्तुलादयः ।
Libra onward use the same six figures in reverse. Work out the gone and coming parts from the Sun.
तद्वदेवैष्यलग्नासूनेवं व्याप्तास्तथा क्रमात् ।
Take off the rising times sign by sign. Turn what is left into degrees of the next sign.