An unusual lunar eclipse arrives late Thursday night. Will you see it in Idaho?
Late on Thursday night, the upper left edge of the moon will begin to darken. By early Friday morning, most of our moon will be in darkness, and may even glow red.
A partial lunar eclipse will pass over Boise, as the moon ducks behind the Earth’s shadow. But to see it, you’ll likely have to head as far away as Nevada, or even California.
This month’s lunar eclipse will be the longest partial eclipse in over 580 years, according to the National Weather Service.
The celestial event will begin just after 11 p.m. Thursday, and will last until shortly after 5 a.m. Friday, for a total of more than six hours.
But a storm coming into the area likely will obscure the view for most Idahoans.
“This weather system is coming right at us,” said Dave Groenert, a meteorologist with the NWS’s Boise office. He told the Idaho Statesman that the view will be obscured “right during the main event” from the Idaho-Nevada border all the way up to the Panhandle.
If any Idahoans do manage to get to a place where the eclipse is visible, it will be hard to see with the naked eye right when it starts, said Brian Jackson, an associate professor in the physics department at Boise State University. Viewing will become easier as the eclipse advances.
Jackson told the Statesman that he recommends committed astronomy enthusiasts stay up until very early Friday morning, when the eclipse will be most visible.
The moon will be most in shadow three minutes after 2 a.m. in Boise, after which the darkness will begin to wane as light seeps through, starting at the upper left corner. While the shadow will never cover the entirety of the moon — making it a “partial” eclipse — it will cover over 99% of the moon at its peak.
The moon is on the opposite side of the Earth from the sun each time the moon appears “full,” Jackson said, but most of the time it doesn’t line up exactly with the earth’s shadow, because the moon’s orbit doesn’t line up with the Earth’s orbit.
“Most of the time, when the moon is full, it’s either orbiting way above the Earth’s shadow … or the moon is below the Earth’s shadow,” Jackson said. “Once in a while, though, the moon’s orbit will align with the Earth’s shadow so that during the full moon we get a lunar eclipse.”
If residents want to give viewing the eclipse a shot in the hopes that the clouds will clear enough to catch a glimpse of what Jackson called a “somewhat unusual” event, there’s no need to head out of town and away from light pollution in order to see it.
“You can see a full moon in your backyard, right?” said David Olsen, president of the Boise Astronomical Society. If they want to, he told the Statesman that intrepid observers could try going up to Table Rock for a more unimpeded view of the sky.
For those who miss the event entirely, Jackson said Boise State will be hosting an astronomy lecture about moons orbiting planets outside our solar system on Dec. 3, which can be tuned into online.
Another lunar eclipse — this one total — will be visible in Boise in May.
But as the longest since 1440, Friday’s 208.4-minute eclipse will not be superseded for a long time, according to Dr. Fred Espenak, a retired astrophysicist with the NASA.
If Idahoans want to see a longer partial lunar eclipse, they’ll have to wait until 2669.
This story was originally published November 17, 2021 at 3:36 PM.
