Tonight does it for the summer of supermoons. At around 9:38 EST, the moon will reach its full stage. This one caps the trio of supermoons that have occurred back-to-back. Also, this one falls closest to the September equinox, it earns the Harvest Moon moniker.
Most people hear Harvest Moon and automatically think fall. Unfortunately, you still need the summer gear, as this year’s will actually mark the final full moon of summer. By the next one we will be breaking out the jackets at night.
While this full moon caps the trilogy of summer supermoons, it won’t be quite as spectacular as the one in August. In July and August, the full moon occurred during the moon’s perigee – the closest point in the Moon’s orbit around Earth. Tonight’s supermoon will also occur during perigee, but August’s full moon was just a bit closer.
What is a Harvest Moon?
We all know what a supermoon is at this point, but what about the Harvest Moon? Let’s dispel the myth of the Moon staying in the sky longer. In reality, the claim to fame for the Harvest Moon is that it rises a little later each night. Other full moons rise 50 minutes later each night. The tighter times allowed farmers more moonlit evenings to harvest crops.
The reason behind the short time lag, is that the Moon is travelling along the part of the ecliptic – the path of the sun in respect’s with the sky. This gives the smallest angle and leads to the moon rising on average 38 minutes later each night. If you are loving life on South Beach, the time extends out to 46 minutes. Pretty sure Miami residents are out harvesting crops, so no loss there.
Those living in the southern hemisphere have to break out the chairs each night. The effect is reversed, with the Moon rising later each night, with an average of 70 minutes.
Amateur astronomers wanting to get the best shots of the final supermoon of the year should have their alarms set for just after 9pm EST tonight. Those of us eager to get to the fall weather should be happy to know by the next full moon, we will be into fall.
A supermoon and a countdown to fall? Hard to complain about that.