The 23 September Equinox: the Time of Year When Night Gains Fastest
The equinox falls on 23 September at 00:05 UT. That day lasts not 12 hours but 12 h 08; true equality waits until the 25th; and above all night is advancing at its top speed: 3.6 minutes gained per day at the latitude of Paris, 5.4 at Helsinki, 2.4 at Athens. Why everything happens now, and what the equinox offers observers.