Definition of Spring Equinox
The spring equinox is the time when, for the northern hemisphere, the day and the night are of equal length. This is when the Sun travels from north to south across the celestial equator, and it ushers in the first day of spring.
It marks one of the quarter days in the calendars of many traditions, with the other quarter days being the summer solstice (or midsummer), the vernal or autumnal equinox and the winter solstice (also called midwinter).
It’s interesting to note that the spring equinox in the northern hemisphere is the autumnal equinox in the winter hemisphere, and vice versa.
TERM OF THE DAY
An ephemeris is a map of the planets. Because the planets are in constant motion, that map is going to change constantly. Ephemerides come in either midnight or noon versions, and show you where the planets are (or were for a date in the past or will be for a date in the future) at either midnight or noon GMT.Read the full Ephemeris definition