This September, skywatchers are in for a treat as the Full Harvest Moon combines with a partial lunar eclipse, offering a rare and spectacular display. On the evening of September 17, 2024, the Full Harvest Moon will rise, marking the second of four consecutive supermoons this year. This supermoon will also coincide with a partial lunar eclipse, creating a unique event that won’t be easily forgotten.
What is the Harvest Moon?
The Harvest Moon is the full moon that appears closest to the autumnal equinox, which this year falls in late September. Its name dates back to times when farmers depended on moonlight to extend their working hours and harvest their crops. This year, the Harvest Moon will rise on September 17, appearing even larger and brighter than usual because it is also a supermoon—a term used when a full moon coincides with its closest point to Earth, known as perigee. While a supermoon only looks slightly bigger to the naked eye, the combination with the Harvest Moon makes it a special sight in the night sky.
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Partial Lunar Eclipse
Adding to the excitement of September’s full moon, a partial lunar eclipse will also occur on the evening of September 17, 2024, and continue into the early hours of September 18. A lunar eclipse happens when the Earth passes between the sun and the moon, casting its shadow on the moon. During a partial lunar eclipse, only a part of the moon enters Earth’s darkest shadow, known as the umbra, which gives the moon a reddish-brown tint—often referred to as a “blood moon.”
For observers in North America, the partial eclipse will begin around 7:41 p.m. EDT and reach its peak—when the moon is most submerged in Earth’s shadow—at approximately 10:44 p.m. EDT. The event will conclude around 11:47 p.m. EDT. For those in Europe and parts of Africa, the eclipse will be visible in the pre-dawn hours of September 18, peaking around 3:45 a.m. BST in London.
Why the Moon Will Appear Different
This partial lunar eclipse is expected to be subtle but captivating. Only a small portion of the moon—about 8.5%—will be covered by Earth’s shadow, creating a darkened upper edge. The rest of the moon will remain bathed in a lighter shadow called the penumbra, which does not block all the sunlight. As a result, the moon will take on a faint reddish-brown hue, giving it a smudgy appearance in the sky. This effect is caused by Earth’s atmosphere filtering the sunlight that reaches the moon, an optical phenomenon similar to the one responsible for colorful sunrises and sunsets.
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This month’s lunar spectacle is particularly notable for its combination of events. The Harvest Moon, supermoon, and partial lunar eclipse will all occur on the same night, a rare alignment that won’t be repeated for several years. While the supermoon will appear about 7% larger than a typical full moon, the partial eclipse will add an extra element of intrigue, making it seem as if a “bite” has been taken out of the moon.