N. Autumnal equinox: Period of time when the sun crosses the equator and day and night are everywhere on earth of approximately equal length. The 2021 Autumnal Equinox falls either on Sep 22 or Sep 23 depending on where you live. So, here's a project to celebrate it! Move your mouse to enjoy the simple parallax. Fact of the Project: In astrology, the autumnal equinox marks the time when the sun enter Libra, the sign of a balanced scales (or day/night lengths). Are you a Libra? Comment any symbol!