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On Friday, a full moon, a lunar eclipse, and a green comet will light up the sky

Here’s how to watch.

Comet 45P/Honda–Mrkos–Pajdušáková 
Brian Resnick is Vox’s science and health editor, and is the co-creator of Unexplainable, Vox's podcast about unanswered questions in science. Previously, Brian was a reporter at Vox and at National Journal.

Yes, it’s the dead of winter. And yes, temperatures will be around freezing in much of the United States. But there are reasons — three, to be exact — to be brave and venture outside.

That’s because Friday night there will be a trio of celestial treats: a full moon, a penumbral lunar eclipse, and a green-headed comet.

First, the full moon and eclipse.

Tonight, the moon will pass through the Earth’s penumbra — the outer region of the Earth’s shadow — which will cast a gray shadow over the surface of the moon. (In a total lunar eclipse, the moon passes through the umbra, or the darkest part of the Earth’s shadow, and that blocks more of the moonlight. During a penumbral eclipse, the moon just darkens slightly.) Most of the country will be able to catch the eclipse during the early evening hours.

Tonight’s full moon will enter the penumbra as it rises in the early evening. “And at maximum eclipse at 7:43 pm you will probably notice a dark grey shading to the Moon’s northern limb,” the Naval Meteorology and Oceanography Command website explains. The eclipse will end around 9:55 pm on the East Coast.

But that’s not all.

At 3 am, a green-headed comet will be at its closest point to the Earth in its journey around the sun. The comet, named 45P/Honda-Mrkos-Pajdušáková (after the Japanese and Eastern European astronomers who discovered it), will be around 7.4 million miles away, or about 30 times the distance of the moon.

The comet will be much harder to spot than the eclipse. For one, the light from the full moon will wash it out. And it will not be bright enough to see with the naked eye. Earthsky reports a pair of binoculars, or a small telescope, could bring it into view, though you might not see more than a smudgy green blob.

To find 45P, look up at the constellation Hercules. Tonight the comet should be in between the great warrior’s “legs.”

If you miss 45P, don’t worry. It completes an orbit around the sun every 5.25 years. Just remember to purchase a telescope in the early 2020s. Or, you can watch a live stream of the comet from Slooh, an astronomy website, right here:

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