Hebrew calendar a (synodic) lunar month, which is 29 days, 12 hours, and 793 parts (there are 1080 "parts" in an hour, so that one part is equal to 3 seconds). The very first molad, the molad tohu, fell on Sunday evening at 11.11, or in Jewish terms Day 2, 5 hours, and 204 parts. In calculating the number of months that will have passed since the known molad that one uses as the starting point, one must remember to include any leap months that falls within the elapsed interval, according to the cycle of leap years. A 19-year cycle of 235
Lunar month month because it is the cycle of the visible phases of the Moon. Most of the following types of lunar month, except the distinction between the sidereal and tropical months, were first recognized in Babylonian lunar astronomy. The period of the Moon's orbit as defined with respect to the celestial sphere of apparently fixed stars (nowadays the International Celestial Reference Frame (ICRF)) is known as a sidereal month because it is the time it takes the Moon to return to a similar position among the stars (): days (27 d 7 h 43 min 11.6 s). This type of month