Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v2.c12.s2.t63.3

v2.c12.s2.t63.3

Translation :—The astronomer, Bāla, wrote this commentary in the Śaka year, denoted by 1547 diminished by the sum of the numbers denoting the month, the nakṣatra, the day of the week, the lunar day, and the half month. The month was the number which is the square root of “the current śaka year reduced by 5 and divided by 31” i.e. √((1524-5)/31) = √49 = 7. The nakṣatra was equal to the month plus 5 i.e. 12th. The day of the week was equal to the nakṣatra reduced by 10, hence 2 or Monday; the lunar day was the 1st and Pakṣa was the 1st”