by Claudine Zap Kiss those long, light days of summer goodbye. September 22 marks the autumn equinox in the Northern Hemisphere " which officially begins at 11:13 pm ET, and marks the return of longer, darker nights. While you can mourn the end of one season, you may find comfort in a glorious harvest moon that will light up the night sky " the first time since 1991 that the equinox and full moon coincide. Of course, that's just in the Northern half of the earth.