The equinox describes the exact same length of time of the bright day and the dark night. Every year there are two days on which this event occurs. At the same time, a new season is heralded. Around 19, 20 and 21 March the calendric spring begins in the northern hemisphere and around 22, 23 and 24 September the calendric autumn; in the southern hemisphere it is the other way round.
At both equinoxes, in March and September, the zenith of the sun crosses the equator. In March, the sun moves from the southern hemisphere to the northern hemisphere. In September the sunzenite crosses the equator again to the south.
In astronomy, the equinox is determined not only by a date, but also by an exact time. This year the sun is on September 23rd at 03:53 a.m. Central European Summer Time in the autumn point.
The two events have always had a special significance for people. At the beginning of autumn the harvest festival was celebrated. In this way we thanked the field and fertility gods. The beginning of spring marks the transition to the warmer season, the flowers bloom and the animal world awakens. The return of the sun is often greeted with fires.