The interval of time between successive passages of the Sun through a node of the Moon’s orbit, when eclipses can occur. It lasts 346.62 days, the length of two eclipse seasons. An eclipse year is shorter than a sidereal year because the nodes of the Moon’s orbit regress westwards around the ecliptic by about 19° per year. There are almost exactly 19 eclipse years in a saros and 57 in an exeligmos.