Astronomy

A Comet, Lunar Eclipse and a 'Snow Moon' Will All Grace Our Skies Tonight

The lucky coincidence of three astronomical events will happen, causing much excitement — but there's a catch.

There are three astronomical "events" occurring all at once tonight, leading to some excitement in social media circles. Alas, on a scale of one to 10 of cosmic awesomeness, this scores a solid six.

So what's all the fuss about? If taken at face value, it all sounds rather promising: there's going to be a lunar eclipse, a "Snow Moon" and a comet all at the same time. While this is all true, I'd like to add a few disclaimers as to what you should really expect, while still getting outside and trying your hand at some astronomy.

There will indeed be a lunar eclipse tonight; in fact it's the first of two lunar eclipses in 2017. But don't go getting excited for a magnificent total lunar eclipse with the moon turning blood red as it passes into Earth's inner shadow. This lunar eclipse is actually going to be a "penumbral lunar eclipse," when the moon passes into the outer shadow of the Earth. When the moon is eclipsed by the central shadow of the Earth, that's when a total eclipse happens - the sun, Earth and moon are in perfect alignment. Any sunlight that refracts through the atmosphere at this time can cause the red hue to occur.

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Penumbral lunar eclipses are different; they are slightly out of alignment, falling into an outer shadow that its partially lit. So although skywatchers will notice a dimming of the full moon between 5:32 p.m. ET to 9:55 p.m. ET (mid eclipse occurs at 7:55 p.m. ET), it certainly won't be as dramatic as a total eclipse. You can watch an animation of what to expect here:

"The outer part of Earth's penumbra is so pale that you won't notice anything until the moon's edge has slid at least halfway in," Alan MacRobert, a senior editor at Sky & Telescope magazine, said in a statement. "So start looking about 90 minutes before mid-eclipse."

If you're not lucky with the weather, you can watch Slooh's live webcast of the event, featuring some expert commentary.

So this brings us to the "Snow Moon." Well, this is probably the biggest letdown - it's just the name given to the full moon of February. That's it. No real astronomical rationale, it's just a fancy name given to February's full moon when, in North America, it's typically cold outside with a chance of snow. As lunar eclipses only happen when there's a full moon, any lunar eclipse that happens in February will be called a "Snow Moon Eclipse." So, it's basically a mediocre eclipse with a cool name - it's certainly no "Supermoon Eclipse."

Saving the best for last, however, there is a touch of the exotic with tonight's skywatching.

A green comet called 45P/Honda-Mrkos-Pajdusakova is currently observable with a small telescope or binoculars and it is expected to peak in brightness in the pre-dawn skies of Saturday. The comet's visible green hue is being caused by vaporizing diatomic carbon. If you want to get outside and try to find it, look toward the constellation of Hercules in the Eastern sky. You can find a handy skywatcher's guide on Spaceweather.com.

Whether or not this astronomical trifecta will live up the the hype, it's a great excuse to get outside and try some amateur astronomy, and if you're able to capture a photograph of the green comet, why not show it off in the comments below, or tweet to @Seeker_Space.

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