DAY OF AUTUMN EQUALITY WHAT IS IT? Astronomical autumn will come in the Northern Hemisphere of the
Earth, and spring will come in the Southern Hemisphere.
Astronomers call this day the day of the autumnal equinox.
On the day of the autumnal equinox,
the Sun rises exactly in the east
and sets exactly in the west, being exactly
12 hours above the horizon and 12 hours below
the horizon, that is, day is equal to night.
Hence the name - equinox. 
