Agni Purana (Jyotisha Selections) · by Vyasa
Chapter 1 · Muhurta: Marriage, Home, Farming
ज्योतिःशास्त्रम्
कालः समागणो वक्ष्ये गणितं कालबुद्धये ।कालः समागणोऽर्कघ्नो मासैश्चैत्रादिभिर्युतः ॥ १ ॥
In the full Agni Purana this is chapter 122, verse 1.
Now I will tell the count of time, a sum for knowing time. Take the count of years. Multiply it by 12. Add the months passed from Chaitra.
Simple meaning: The sum starts here: multiply the years passed by twelve and add the months since Chaitra.
सप्तविंशतिशेषस्तु ध्रुवो नक्षत्रयोगयोः ।
The remainder by twenty-seven starts the star count. Each month adds one weekday and thirty-two time units.
द्वे पिण्डे द्वे च नक्षत्रे नाड्य एकादश ह्यृणे ।
Each month the figures gain two, two and eleven. Add the moon day and divide by seven for the weekday.
शेषवाराश्च सूर्याद्या घटिकासु च पातयेत् ।
The remainder gives the weekday from Sunday. Add the moon day to the Moon's figure and divide by fourteen.