Equinox and Solstice

The points of intersection of the Ecliptic and the celestial equator  are called the nodes or more commonly the equinoxes. Currently the vernal, or spring, equinox occurs around the 21st of March. The autumnal equinox occurs around the 23rd of September. Midway between the equinoxes are the winter solstice around the 22nd of December and the summer solstice, the 21st of June. ( Solstice means 'sun stands still' )

Because the equator and the ecliptic rotate in opposite directions to each other the position of the equinoxes on the ecliptic moves about one degree every seventy years. ( It takes 25,868 years for the ecliptic and the celestial equator to return to the same relative positions).