The sun, moon and Earth line up every month. That, in itself, is nothing extraordinary.
For most of those months, the moon’s orbit is at a slight angle from the Earth’s shadow.
“The moon is either too high or too low, and we just have a normal full moon,” said Andy Veh, a physics professor at Kenai Peninsula College. “But every six months, every six full moons, the moon actually orbits through the moon’s shadow. And that’s when we have a lunar eclipse.”
But observers from any given spot on Earth will see them less often, depending on whether they’re experiencing night or day when an eclipse happens.
There’s going to be a total lunar eclipse late Tuesday night — or, early Wednesday morning — which will be visible in much of Alaska. Those who can stay awake until 3:18 a.m., when the eclipse peaks in Juneau, will see a red-tinted full moon just over the horizon.
That’s if you can see the moon at all. Cody Moore, a meteorologist at the National Weather Service office in Fairbanks, says the prospects aren’t good in Southeast.
“There is a chance for a few breaks, but viewing weather does not look optimal,” he said.
Moore said the forecast for Haines and Skagway looks a bit drier, so people there might have a better chance of catching a glimpse.
The moon will appear slightly red during this week’s eclipse because the Earth’s atmosphere scatters, or refracts, the light coming through from the sun. Red is the least refracted of all the colors of light, which is why it’s the one we can see.
As with the aurora, the color can come out more vibrantly in photos. Also like the aurora, it’s more just a cool phenomenon to witness than anything else.
But Veh said there did used to be a greater significance to the lunar eclipse.
“The shadow on the moon is somewhat round. It’s not a straight line,” he said. “So way back when — I’m talking 2,000, 3,000 years ago, when people really didn’t know how the Earth was shaped — during the lunar eclipse, they saw it. They saw a round shadow of the Earth on the moon during the lunar eclipse, and concluded from that, we must be living on a round Earth.”
It’s a treat to have a visible astronomical event during the summer. The lack of darkness makes it so there’s usually not much to see.
“In the summer, it’s not much worth doing astronomy,” Veh said. “Because you have like two hours and kind of twilight going out, and you’re not going to see much.”
Still, this viewing is not without its obstacles.
The moon will be low to the horizon. Veh recommends getting somewhere you can see clearly, like a beach, and looking south.
“If you go to your backyard, it’s actually not going to work,” Veh said. “Because you have trees in the way.”
The partial lunar eclipse starts close to 2 a.m. and ends near 5 a.m. on May 26. Note that’s after midnight Tuesday, in the early hours of Wednesday.
Peak eclipse — when the moon is almost entirely covered — will start around 3:11 a.m. and end at 3:25 a.m.
Unlike the solar eclipse, you don’t need any sort of eye protection to watch this one.
For exact timing on this eclipse, click here.