Despite the disruption, at least skywatchers will have something to look forward to this weekend with a full moon and lunar eclipse set to appear in the night sky on the evening of July 4 and early morning of July 5. Here’s what you should look out for.
At 11:07 p.m. EDT on July 4, the full moon will pass through the more diffuse, outermost part of the Earth’s shadow, called the “penumbra,” causing what’s known as a “penumbral lunar eclipse.”
Unlike total and partial lunar eclipses, penumbral lunar eclipses are much more subtle. At best, astute observers this weekend may notice a slight darkening of one section of the moon.
“A penumbral lunar eclipse happens when our moon is ‘kissed’ only marginally by the most external regions of the structure of the Earth’s shadow,” astronomer Gianluca Masi, from the Virtual Telescope Project, told Newsweek.
However, these eclipses can sometimes be hard to see because the parts of the moon covered in shadow are only slightly fainter than the rest of the lunar surface.
Nevertheless, you can maximize your chances of seeing something if you look up at the full moon close to 12:29 a.m. EDT on June 5, when the peak of the eclipse will occur. This is when the largest part of the lunar surface will be covered in shadow. The entire event will end at 1:52 a.m. EDT on July 5 when the moon passes out of the Earth’s penumbra.
Technically, the eclipse should be visible from all of the United States, as well as much of the rest of North America, South America, southern and western Europe, and much of Africa.
However, if your viewing is hampered by cloudy skies or you are struggling to see the eclipse, the Lowell Observatory in Flagstaff, Arizona, will be providing a livestream of the event on YouTube, which will include an interactive stargazing session.
Lunar eclipses can only happen when the moon is full, i.e., when the Earth is located directly behind the sun and the moon, and all three bodies are lined up in the same plane. In these moments, which occur roughly once every month, the moon appears fully illuminated, like a perfect circle.
This alignment technically occurs at a specific moment in time, which will be 12:44 a.m. EDT, July 5. But the moon will appear full to most people for about a day either side of this point. In North America, the full moon in July is often referred to as the “Full Buck Moon” because, at this time of year, the antlers of male deers finish growing.
