Equinox (celestial coordinates)

In astronomy, equinox is a moment in time at which the vernal pynt, celestial equator, an ither such elements are taken tae be uised in the defineetion o a celestial coordinate seestem. The poseetion at ither equinoxes can be computit bi takin intae accoont precession, nutation an aberration, which directly affect e.g. richt ascension an declination.