It will look like Godzilla took a nibble out of the Harvest Moon.
The Harvest Moon rises on Sept. 17. It will continue to look full and round for some days afterward and, on Sept. 18, will grow into a big fall supermoon. But just hours before becoming a supermoon, the shadow of planet Earth will enter the scene, cast itself upon the moon, and dim its ochre glow.
This is a lunar eclipse.
Astronomers point out that full moons always happen at night—it’s simply a law of physics. The moon must be directly opposite the sun with respect to the Earth to appear full. The condition is even stricter with lunar eclipses because only when the moon is exactly opposite the sun will it pass through our planet’s acute conical shadow. There, all sunlight is completely obliterated.
Lunar eclipses are not extremely common; there are only two in 2024.
The moon will first enter the area of Earth’s shadow where the sun is still partly visible, called the penumbra, and cause a general darkening of the lunar surface. Next, it will partially be swallowed by that conical shadow of total darkness, the umbra. When this happens, it’s called a partial lunar eclipse (a total lunar eclipse is where the moon is fully covered by Earth’s umbral shadow). A little black bite mark on the moon will appear—Godzilla, it might seem, has been by.
The eclipse can be seen only from places where it’s nighttime on Earth. These places include eastern North America, all of South America, western parts of Europe and Africa, and parts of Antarctica. At least some of the eclipse may be glimpsed either at moonrise in areas of the Midwest and western North America or at moonset in eastern parts of Europe and Africa.
The Partial Lunar Eclipse Schedule and How to View It
The partial eclipse begins at 10:22 p.m. EDT on Sept. 18 and ends at 11:16 p.m. EDT the same evening. For a little over an hour both before and after the partial eclipse, a penumbral eclipse—when the Earth’s penumbral shadow is cast upon the moon—will effectuate a subtle shading across the entire lunar sphere.Midway through the lunar eclipse, the moment of greatest eclipse (when the largest percentage of the moon is blotted out) will occur at 10:44 p.m. EDT. At this time, about 8 percent of the moon’s surface will be covered by Earth’s dark umbral shadow. The event will occur directly over Brazil’s easterly coast.
Unlike solar eclipses, lunar eclipses are completely safe for viewing without eye protection. You won’t need binoculars to observe it either, though that might add to your moon-watching enjoyment!
Observers may locate the eclipse appearing in the constellation Pisces. It’s also possible to see a bright, star-like object shining beside the eclipse. This is the planet Saturn—where, presumably, Godzilla is hiding out in its rings, munching on moon crumbs.
