As the sun shines on Earth, it creates three distinct long shadows in a triangular shape behind it. The darkest of these, as you can see in the video above, is a triangle within the wider triangle, known as the umbra. But on each side of the umbra is the penumbra, lighter shadows, accounting for some of the sun’s rays that manage to sneak by our orb.
As it orbits Earth, the moon passes through these shadows on a (somewhat) predictable basis, creating shades of colors on the moon one doesn’t commonly see. In a full lunar eclipse, for example, when the moon passes through the umbra, it goes red, creating a blood moon. But Friday it will only go a little bit darker, as it will only be passing through the penumbra.
You should try to see it! Which you can as long as you don’t live in Australia, or parts of East Asia and Alaska, where it will not be visible. At 7:43 p.m Eastern time, look up at the sky, hope that it’s not cloudy, and experience your moon, since it will also be full (a requirement for eclipses).
Eclipse or not, the February full moon has long been referred to as the “snow moon,” which, according to Farmer’s Almanac, was one of a number of nicknames given to various moons by American Indians.
Meanwhile, around seven-and-a-half hours after eclipse, while the snow moon is still snow mooning, a comet, called 45P, will streak across the sky. The comet will fly by around 7.4 million miles from Earth, which should make it visible if you look to the east around 3 a.m., according to USA Today. Seeing it with the naked eye might be a challenge, though, so try using binoculars or a telescope if you have one.
If you miss the penumbral lunar eclipse, you will have to wait until at least 2018, as astronomers say it will be this year’s only one (lunar eclipses happen up to five times a year, with only a third of those being penumbral.) But if you miss the comet you’ll be in for a slightly longer wait, as it won’t fly by again until 2022.