Greetings fellow mariners.
At 0650 today we said goodbye to celestial summer and hello to celestial autumn. What does that mean? The September equinox is the moment the sun appears to cross the celestial equator (the celestial equator is a projection of the terrestrial equator into outer space).
At the equinox, the sun as viewed from the equator rises due east and sets due west. Before this equinox the sun rises and sets slightly more northerly, and after the equinox rises and sets slightly more southerly - check it with a compass in Dec if you don't believe me.
During the equinox, the Earth's axis and its orbit line up so that both hemispheres get an equal amount of sunlight (hence equinox from the Latin words aequi, which means "equal," and nox, which means "night."). it goes downhill from there in Autumn but in Spring it gets better. For us now, our sunrise will become later, sunsets will be earlier, the change in equinox encourages the trees to change to their autumn colours. This is also the time of year when sun CME activity sparks even more visual displays of the Northern lights.
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This photo shows the significant height difference and length of day through the seasons |