Cancel all your plans immediately: tonight, stargazers will be able to view a penumbral lunar eclipse, a stunning full moon, and a comet flyby. Itll make for a fantastic Friday night, and its totally free!

Its worth noting that lunar eclipses only occur during a full moon, but penumbral lunar eclipses are still pretty special, albeit subtle. These sorts of eclipses occur when the Moon enters the outer region of Earths shadow, called the penumbra. Observers will notice an unusual dark shade toward the top of the moon when it reaches mid-eclipse, since this will be the region closest to the Earths full shadow, called the umbra. Since penumbral eclipses are more subtle than partial eclipses, stargazers will have to look carefully to see this slightly darker shadeunless they live in Australia or Japan, where the eclipse wont be visible at all. Sorry, guys.

For those who plan to watch, remember to look up at 7:43PM ET (4:43 PT)thats when the Moon will be darkest. Every year, two to five lunar eclipses occur, and one in every three will be penumbral. However, this will be the only penumbral lunar eclipse of 2017.

Farmers Almanacs have long referred to the full moon in February as the snow moon. The snow moon name allegedly traces backhundreds of years, to Native Americans who used the name to keep track of seasons. The full moon in February was associated with a cold and snowy month that made hunting difficult, and thus, the snow moon was born. Its also sometimes called the hunger moon.

But with comet 45P coming into join the party, this eclipse will be extra special. The comet is a Jupiter family comet, meaning its orbit is determined by Jupiters gravitational pull. Its believed that such comets originated in the Kuiper Belt, where an abundance of icy-rock clusters are organized just beyond Neptunes orbit. There are roughly 400 Jupiter family comets that we know of, though comet 45Ps greenish glowwhich comes from the diatomic carbon in its nucleusmakes it a little more special.

Youll have to stay up a little longer to see comet 45P, which will whizz by Earth around 3AM ET. This particular comet is a fast one, traveling at about 51,000 miles per hour, and only visits Earth twice per decade. Unfortunately, comet 45P wont be visible to the naked eyeyoull need a telescope or binoculars to view it.

Dont let this opportunity fly bycomet 45P wont come this close to Earth again until 2022. Slooh will be broadcasting live views of the snow moon starting at 5:30PM ET (2:30PM PT), and a live stream for the comet starting at 10:30PM ET (7:30 PM PT). You can check it all out below:

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How to Watch Tonight's Ultra Rare Eclipse and Comet Flyby - Gizmodo