Everything you need to know about the autumnal equinox of 2010
Here are some sky highlights of this 2010 September equinox. If your sky is clear, you can glimpse an almost full Harvest Moon in the east after sunset on this equinox evening. The crest of the moon’s full phase will come only 6 hours after the exact moment of the 2010 September equinox – in early morning tomorrow for the U.S. and Europe (4:17 a.m. Thursday morning Central Daylight Time, or 9:17 Universal Time).
This is the northern hemisphere’s legendary Harvest Moon and the southern hemisphere’s first full moon of spring.
What’s special about the Harvest Moon?
What’s more there’s a blazing starlike light near tonight’s moon. It’s the solar system’s largest planet Jupiter, which just yesterday reached its opposition – when Earth flew between Jupiter and the sun.
The full moon won’t fall on the September equinox again until the year 2029. And Jupiter’s next comparably good appearance on the September equinox won’t happen for another 12 years.
By the way, the sun sets due west on this day of the equinox, the first day of autumn for North America. Many people write to us around this time, trying to comprehend how that can be so. And it is really tough to understand without a three-dimensional visual aid – maybe one of those plastic celestial globes. Just remember, we all see the same sky. And on the day of the equinox, the plane of Earth’s equator is intersecting the ecliptic – or plane of Earth’s orbit around the sun. That’s a fancy way of saying the sun is on the celestial equator. This celestial equator intersects your horizon at points due east and due west. And that’s why today – September 22, 2010 – the sun rises due east sets due west as seen from all across the globe. That makes today a good day for finding due west from your yard or other favorite site for watching the sky.
So happy equinox, and enjoy Jupiter and the nearly full Harvest Moon tonight! They will rise at sunset on this 2010 equinox evening and shine in the sky throughout the night.
Fastest sunsets around equinox time
Autumn equinox, cycles of nature and Chinese philosophy