The Autumnal Equinox marks the moment when the sun is directly above the equator, and day and night are of equal length. For many cultures, it signals the start of the harvest season and is celebrated as a time of thanksgiving. In the Northern Hemisphere, the Autumnal Equinox falls on September 23rd, while in the Southern Hemisphere it occurs on March 20th or 21st. For most people, the arrival of Autumn brings cooler temperatures and shorter days. However, for those living in the Southern Hemisphere, it heralds the start of Spring.
Grey line or gray line propagation is a form of radio signal propagation that provides surprisingly long-distance DX radio communications at dawn and dusk sometimes when other forms of ionospheric propagation may not be expected to provide signal paths of these distances.
And if you look at the latitude (up and down) of the sun today, you will see that it sits over the equator: a point halfway in its biennial journey between its position over the Tropic of Cancer in June and its position over the Tropic of Capricorn in December. But of course, as a user of the extensive Grey line features of the Global Overlay Mapper program, you already knew that.