The longest partial lunar eclipse in centuries is set to coincide with next week’s full moon, in an hourslong event that will be visible across North America and many other parts of the world.
The Beaver Moon is expected to reach its peak next Friday at 1 a.m. PST, according to the Farmer’s Almanac.
But don’t expect to see the moon fully illuminated at that point. That’s because the celestial body will be mostly blocked by the Earth’s shadow for a few hours around then, creating a near-total eclipse that will be visible to a large swath of the planet, NASA reports.
On the West Coast, the partial eclipse will begin shortly after 11 p.m. on Nov. 18 and will hit its maximum just after 1 a.m. on Nov. 19— about the same time the moon is expected to be at its fullest.
The celestial event will be visible to the naked eye, but for areas experiencing poor visibility at the time, it can also be viewed online here and here.
In total, the partial lunar eclipse is expected to last 3 hours and 28 minutes, making it the longest one not just of the 21st century, but in more than 580 years, NASA records show.
It’s also expected to be the longest partial lunar eclipse in more than 1,000 years. In the future, there won’t be a longer one until Feb. 8, 2669, when NASA forecasts one with a duration of 3 hours and 30 minutes.
Factoring in when the penumbral eclipse begins and ends (which happens before and after the partial one), the Nov. 18 and 19 event’s entire duration is about 6 hours, the federal space agency reports.
The Nov. 18 and 19 eclipse will be visible in North and South America, the Pacific Region, Australia and Eastern Asia, so long as weather permits.
“Partial lunar eclipses might not be quite as spectacular as total lunar eclipses – where the Moon is completely covered in Earth’s shadow – but they occur more frequently,” NASA stated on its website. “And that just means more opportunities to witness little changes in our solar system that sometimes occur right before our eyes.”
Every year there are between two and five lunar eclipses, according to the space agency. This year, a total lunar eclipse combined with a supermoon to create a super “blood” moon in May.