Tonight’s the night when a lunar eclipse dims the full moon, and when a recently discovered green comet comes closest to our planet. But unless you know what’s coming, you’re almost certain to miss them.
You may miss them anyway, depending on the sky conditions. The Friday night forecast for the Seattle area calls for partly cloudy skies with a 20 percent chance of rain.
Despite Seattle’s odds, it’s worth watching for moonrise around 5:30 p.m. PT on the eastern horizon. By then, the penumbral lunar eclipse will be past its peak (which comes at 4:44 p.m. PT, before Seattle’s sunset). But assuming the skies are clear, you should still be able to make out the faint darkening of the moon’s edge that’s caused by Earth’s shadow.
The farther you are from urban haze, the better the viewing conditions will be. “You can even use this event to check the acuteness of your visual perception,” Kelly Beatty, Sky & Telescope’s senior editor, notes in an eclipse preview.
The penumbral shadow fades out of visibility by 6:15 p.m. After that, we’ll be looking at the typical full moon for February.
Each month’s full moon has a nickname, and this one is called the “Snow Moon” because its glow is supposed to brighten up fields of snow. (Whoever came up with this definitely didn’t live in Seattle.)
There’s also a super-sparkly Venus visible high in the southwest, with a butterscotch Mars to its upper left.
Tonight’s other sky highlight is the close encounter with Comet 45P/Honda-Mrkos-Pajdusakova, which was discovered back in 1948. The comet rounds the sun every five years or so, but this time it’s coming relatively near Earth. It’ll be a mere 7.4 million miles from us at midnight PT, its time of closest approach.
Telescopes reveal that the comet has a beautiful green glow, due to the fluorescing carbon gas in its coma. But don’t expect to see that with the naked eye. You’d be lucky to spot the comet even with binoculars.
Once again, the way to maximize your chances is to find a spot with clear, dark skies. Our meteor viewing guide provides some suggestions for the Seattle area.
If you want to give it a try, make a close study of the sky maps provided by Sky & Telescope, Heavens Above and Astro Bob (a.k.a. Bob King). Comet 45P is in the constellation Hercules, which rises in the east around 1 a.m. Saturday. If you can make it out, the comet would look like a fuzzy green patch, or a puff of green smoke.
Don’t get your hopes up, even if you’re packing a telescope: King says spotting the comet tonight will tricky due to the full moon’s glare. But the prospects should improve in just a few days.
“Come Valentine’s Day, 45P will have motored into northern Bootes and appear in the east around 10 p.m. before moonrise,” King writes.
You’ll still probably need a telescope to see it, “but at least we’ll get to see it in a dark, dark sky until it fades from easy viewing later in the month,” King says.