mark@hp-pcd.UUCP (09/24/83)
#R:cbosgd:-32700:hp-kirk:7200006:000:978 hp-kirk!mark Sep 22 09:18:00 1983 On the average the moon will complete a trip around the earth in 27 days, 7 hours, 43.2 minutes (this is the sidereal period); however, the lunar month (which is the more relevant period) is the time from one new moon to the next new moon and due to the earth's motion around the sun, this period (the synodical period) is about 29 days, 12 hours, 44.05 minutes. This latter figure works out to a lunar month of 29.5306 days. The seasons are based on the tropical year which today is about 365 days, 5 hours, 48.75 minutes (but has been decreasing by about .5 seconds per century). This works out to a tropical year of 365.2422 days. Given all of this there are 12.3683 lunar months in a tropical year. The closest whole number values result in a year consisting of 12 months of 30 days each. from the almanac of Mark Rowe hp-cvd!mark Corvallis, Oregon