A rare celestial event treated skywatchers who were up early as a total lunar eclipse graced the skies early Tuesday morning.

The total lunar eclipse and Beaver Moon happened on Tuesday, Nov. 8 (Election Day), and it will be the last total one for another three years. (Although space fans can still enjoy partial and penumbral lunar eclipses.)

This year’s total lunar eclipse was seen by those in North and Central America and other parts of the world, such as Australia, eastern Asia, northeastern Europe, and much of South America, said Dr. Kristen Thompson of Davidson College in Davidson, North Carolina.

And here are a few things to know about a total lunar eclipse.

A few lessons about a total lunar eclipse

“In a total lunar eclipse, the sun, moon, and Earth are all lined up, so that the moon passes through Earth's shadow,” explained Dr. Roy Gal from the Institute for Astronomy at the University of Hawaiʻi at Mānoa.

So why aren’t there lunar eclipses every month? Gal has an answer for that too. The moon’s orbit around the Earth is at a tilt and because of this, the moon is either above or below the line connecting the sun and Earth, missing the planet’s shadow.

“If the moon's orbit was exactly aligned with the Earth's orbit, we would get one lunar eclipse every month (at full moon) and one solar eclipse every month (at new moon). Instead, we only get eclipses when the moon, on its tilted orbit, passes through the Earth's orbit when the moon is opposite the sun (lunar eclipse) or in the sun's direction (solar eclipse),” he said.

And lunar eclipses can only happen during the full moon since the sun has to be on the very opposite side to the moon, explained José Cotayo, an education specialist at Tampa’s Museum of Science and Industry.

“This orientation of sun, Earth and moon actually happens every single month when the moon reaches its full phase, but the moon orbits our planet at a slight 5 degree tilt … that’s just enough of a difference to cause the moon to sometimes only cross through the umbra (partial lunar eclipse) or to miss our shadow completely,” he said.

And that 5-degree tilt can determine what type of celestial wonder the people of Earth get to see.

“Moreover, not all eclipses are total. For example, the 5-degree tilt of the moon’s orbit could carry only a portion of the moon through the darkest part of Earth’s shadow, resulting in a partial instead of a total eclipse,” said Thompson.

But when the Earth, its lunar sister and the sun are all aligned, the moon turns red. Or appears red.

Dr. Yan Fernandez from the University of Central Florida said the reason why the silvery moon changes color is due to the way light passes through the Earth’s atmosphere.

“You know how the sky near the sun at sunset and sunrise is red? Redder light passes through the atmosphere even when the bluer light gets scattered away. The moon looks red because all the red light from all the sunsets/sunrises going on on Earth at the time of the eclipse is passing through the atmosphere and so heads to the moon. The light reflects off the moon back to us, making it look red,” he said.

And Thompson said that during totality, the moon will take on a reddish hue, creating the illusion of a “blood moon.”

Who can see the lunar eclipse?

Those in certain parts of the world could watch this year’s total lunar eclipse and there is a reason for it.  

“The way that the sun, Earth, and moon are lined up for our shadow to fall on the lunar surface means that only observers on the nightside of Earth can see a total lunar eclipse,” Cotayo explained.

Those on the dayside of the planet, Cotayo continued, would only see the sun, as normal.

Thompson also explained that depending on where a person is, the moon may or may not be above the horizon for the duration of the eclipse.

“Everyone in the U.S. will get to see at least some of the eclipse, but, depending on your location, the moon may or may not be above your horizon for the duration of the eclipse. Those in the western U.S. will get to see the whole event while those along the east coast will get to see totality but the moon will set before the final partial eclipse ends,” she said.

Is it safe to look at a total lunar eclipse?

Yes, say Gal, Cotayo, Thompson and Fernandez.

“It's safe, even through a telescope or binoculars. Solar eclipses are the ones that are dangerous, but lunar eclipses are fine,” commented Fernandez.

And Cotayo had some advice on how to watch the lunar dance.

“I encourage anyone interested in observing the moon during a lunar eclipse to do so at several key intervals — right before the moon crosses into Earth’s shadow when it’s halfway through the penumbra, totality, and the reverse,” he advised.

What will a total lunar eclipse look like while on the moon?

If all goes according to NASA’s plan, the Artemis III mission is expected to happen in 2025, which will see humans returning to the moon’s surface.

And the next total lunar eclipse is in 2025. So let’s say the Artemis III astronauts are on the moon during a lunar eclipse, what exactly will they see?

A total opposite of what we will see.

“What's cool about that is that a total lunar eclipse for us means a total solar eclipse for anyone on the moon!” exclaimed Fernandez.

And Gal explained the Earth would appear much bigger to the Artemis astronauts.

“There is a big difference — the Earth would appear much bigger (in) the sky, because it is about four times the diameter of the moon. So they would see a very long-duration solar eclipse — while we on Earth would see an equal-duration lunar eclipse,” he said.

The most fascinating thing about lunar eclipses

Each one of these educational experts shared their thoughts about lunar eclipses.

“Personally, I think there are two aspects to lunar eclipses that are fascinating. First, we understand the motions in our solar system so well that we can predict with incredibly high accuracy, and for centuries into the future, when there will be lunar eclipses and where exactly on Earth they will be visible.  That's clear evidence that science has predictive power and maybe listening to scientists can be a good idea. On the flip side, they are also amazing and beautiful, and a clear demonstration of how humans from all over the world share the same sky and have for millennia wondered about how the universe works and just what is out there in the vastness of space,” shared Gal.

“The light from all the simultaneous sunrises and sunsets being cast onto the moon after passing through our atmosphere giving it that reddish glow,” stated Cotayo.

“Total ones are fun to watch because it lets you watch things move in the Solar System in real-time. Over the course of a few hours, you can see the moon move in and out of the shadow. Plus the optical effects are a bonus. The other reason I like them is because they make me think back to thousands of years ago when people were just starting to figure out our place in the Universe. With some careful observations of lunar eclipses and some math you can actually figure out things like how far away the moon is and how large the moon is. We're used to thinking of such things as the kind of discovery that was only possible relatively late in our civilization. But there's a lot we learned about the Universe even before the telescope was invented just by watching the sky and being careful about it,” Fernandez said.

“During a lunar eclipse, the amount of reflected sunlight is reduced, making the moon appear less bright than a typical full moon. Lunar eclipses are astronomical events that you can safely stare at for hours,” said Thompson.