Fall doesn't come all at once with equinox; it's been coming since the 26th of June when the days started to grow longer again, the Northern Hemisphere tilting away from its source of heat. The sun rose from the east northeast and set west northwest three months ago; now it rises almost due east, sets due west. Dawn and dusk continue to move south at the rate of about one degree every 72 hours until December solstice. The night sky is changing too, the stars predicting winter. By nine o'clock,