At nine minutes past three this morning, GMT, the sun was overhead the equator.  To celebrate, here are a few things that you may or may not know about the equinox. Only one of them is not true.

The sun will rise due east and set due west for everyone today.

The direction (bearing) of sunrise and sunset changes by more each day at this time of year than at any other time.

On the December side of the equinoxes the sun is always overhead the southern hemisphere, on the June side it is always overhead the northern hemisphere.

Everyone on the planet shares an equal length day and night on the equinoxes.

Satellites that appear stationary and stay over the same spot on the Earth’s surface are called geostationary or geosynchronous and they remain in orbit over the equator. As the sun passes over the equator at the equinoxes, it passes behind these satellites and can cause interference in telecommunications.

Many of the world’s religions observe the autumnal equinox, including the Druids and the Native American tribe, the Chumash.

Eggs can be balanced on their end on the equinoxes.

If the sky is clear we will get a very good view of Mars in the east in the early evening. Sitting between the constellations of Leo (easy to find) and Cancer (hard to find), it will be rising about thirty degrees north of east at dusk and pass through due east at 8.30pm. By then Orion, below the high moon, will have moved to occupy a large part of the southern sky. If you follow Orion’s belt down to nearer the horizon then low in the southeast you will see the brightest star of them all, Sirius.

If you do happen to be awake late, then Mars will have moved to be due south and high in the sky by 1am. By this time the moon will have begun its steep descent in the west. If you are enjoying this in fresh air then you will either be very cold, or the owner of some excellent outdoor kit.

In this picture the horizon is well above sea level because of the hill, so we have to bear in mind that the angle the sun makes to the horizon will be 90 degrees minus our latitude, ie. our colatitude.