I tend to get a little confused by some of the terms when I read about astronomy. For instance, when I looked up equinox on Wikipedia, it reads,
“At an equinox, the sun is at one of two opposite points on the celestial sphere where the celestial equator (i.e. declination 0) and ecliptic intersect. These points of intersection are called equinoctial points: classically, the vernal point (RA = 00h 00m 00s and longitude = 0º) and the autumnal point (RA = 12h 00m 00s and longitude = 180º). By extension, the term equinox may denote an equinoctial point.”
That's a little over my head.
I know that the equinox ( from the Latin for “equal nights”) are when the day and night are the same length. It’s the beginning of spring or fall, depending on what hemisphere you are in.
Actually, the days and nights are not strictly 12 hours each. The real definition of the equinox is when the earth, which generally tilts either toward or away from the sun depending on its position in orbit, is now parallel to the sun.