Molad based on a constant interval cycle that is widely but incorrectly regarded as an approximation of the time in Jerusalem of the mean lunar conjunction. Each "molad" moment occurs exactly 29 days 12 hours 44 minutes and 3+/ seconds (or, equivalently, 29 days 12 hours and 44+/ minutes) after the previous "molad" moment. This interval is numerically exactly the same as the length of the mean synodic month that was published by Ptolemy in the Almagest, who cited Hipparchus as its source. Although in the era of Hipparchus (2nd century BC) this interval was equal to the average time between
Karkaṭa followed by the solar month of Siṃha. The Karkata month is called "Adi" in the Tamil Hindu calendar. The ancient and medieval era Sanskrit texts of India vary in their calculations about the duration of Karkata, just like they do with other months. For example, the "Surya Siddhanta" calculates the duration of Karkata to be 31 days, 11 hours, 24 minutes and 24 seconds. In contrast, the "Arya Siddhanta" calculates the duration of the Karkata month to be 31 days, 11 hours, 13 minutes and 36 seconds. The Indian solar month names are significant in epigraphical studies of South Asia.