Gerald Kelleher wrote:
The pivoting circle of illumination off the Equator on an Earth with a
zero inclination was something I first saw in Wikipedia 'Seasons' article
and it still remains that way -

https://en.wikipedia.org/wiki/Season

This was extended last year by NASA and the APOD website

https://apod.nasa.gov/apod/ap170319.html


Again and again the explanations now term the Equinox as the Sun
directly over the Equator when the Equator always presents the same
daylight length throughout an orbit.


Another thing which individuals are keen to jump in it that
daylight/darkness is not equal on the Equinox and fiddle about with the
tiny variations while they completely ignore the Polar day/night cycle
where daylight extends beyond 6 months so no, not all parts of the Earth
experience a daylight/darkness symmetry.

The recent uptake of the pivoting circle of illumination explanation is
alarming, even for this mind accustomed to wayward notions of motions,
orientation and so on. Wish I could give people credit for undoing this
mess or better still - working towards explaining the proper mechanisms
for the Equinox and the seasons but unfortunately not again this year or
any other year previously despite the spectacular productive research the
mechanism contains.


On the equator the Sun is only directly overhead on the equinoxes. In the
northern summer the sun is always to the north and in the southern summer
it’s always to the south. At the equinoxes and only at the equinoxes it’s
directly overhead at noon.