Full moon and the names "harvest moon" and "hunter's moon" for the full moons of autumn. The "harvest moon" and "hunter's moon" are traditional terms for the full moons occurring during late summer and in the autumn, in the northern hemisphere usually in September and October respectively. The "harvest moon" is the full moon closest to the autumnal equinox (22 or 23 September), coming anywhere from two weeks before to two weeks after that date. The "hunter's moon" is the full moon following it. The names are recorded from the early 18th century. The "Oxford English Dictionary" entry for "harvest moon" cites
Equinox Iranian calendars as Nowruz (means new day), while the autumnal equinox (September) marks the beginning of autumn. When Julius Caesar established the Julian calendar in 45 BC, he set 25 March as the date of the spring equinox; this was already the starting day of the year in the Persian and Indian calendars. Because the Julian year is longer than the tropical year by about 11.3 minutes on average (or 1 day in 128 years), the calendar "drifted" with respect to the two equinoxes — so that in AD 300 the spring equinox occurred on about 21 March, and by