Islamic calendar lunar months begin precisely at the time of the monthly "conjunction", when the Moon is located most directly between the Earth and the Sun. The month is defined as the average duration of a revolution of the Moon around the Earth (29.53 days). By convention, months of 30 days and 29 days succeed each other, adding up over two successive months to 59 full days. This leaves only a small monthly variation of 44 minutes to account for, which adds up to a total of 24 hours (i.e., the equivalent of one full day) in 2.73 years. To settle accounts,
Adhik Maas "adhika"; "maal", "māla"; "maas", "maasa", "mās", "māsa", "mas", "mass". This is the thirteenth month of the lunar calendar. Adhik Maas adopts the name of the month that follows. Purushottam Maas is considered inauspicious and no activities like weddings or moving into a new house are conducted. It is a time for prayer, fasting, charity, and self-improvement. According to "Vasishtha Siddhantha" (the treatise of Vasishtha), Purushottam Maas or the extra lunar month occurs after every 32 months, 16 days and 8 "ghati". (A "ghati" is th of a sidereal day, approximately 24 minutes, so 8 "ghati" is about 3 hours.) In