Hebrew calendar (astronomically called a lunar conjunction and, in Hebrew, a molad) is the moment at which the sun and moon are aligned horizontally with respect to a north-south line (technically, they have the same ecliptical longitude). The period between two new moons is a synodic month. The actual length of a synodic month varies from about 29 days 6 hours and 30 minutes (29.27 days) to about 29 days and 20 hours (29.83 days), a variation range of about 13 hours and 30 minutes. Accordingly, for convenience, a long-term average length, identical to the mean synodic month of ancient times (also
Vṛṣabha the Tamil Hindu calendar. The ancient and medieval era Sanskrit texts of India vary in their calculations about the duration of Vrsabha, just like they do with other months. For example, the "Surya Siddhanta" calculates the duration of Vrishabha to be 31 days, 10 hours, 5 minutes and 12 seconds. In contrast, the "Arya Siddhanta" calculates the duration of Vrsabha to be 31 days, 9 hours, 37 minutes and 36 seconds. The Indian solar month names are significant in epigraphical studies of South Asia. For example, "Vrsabha" month, along with other solar months, are found inscribed in medieval era Hindu