A Comet, Eclipse and a Full Moon Will Light Up the Skies Friday Night

There will be a lot going on in the night sky, including a pass by the green comet 45P/Honda-Mrkos-Pajdušáková

Comet 45P/Honda-Mrkos-Pajdušáková during its last pass in 2011 NASA/JPL-Caltech

This time of year, cabin fever often starts to set in across much of North America as the late days of winter set in. But on Friday, there’s a great excuse—actually several excuses—for venturing outdoors. That’s because there will be a penumbral eclipse, a full moon and a fly-by of an emerald green comet all on the same night.

The unusual celestial triple play begins early Friday evening, reports Weather.com. Starting at 5:34 P.M. eastern time, people along the east coast will be able to observe a penumbral lunar eclipse, when the sun, moon and earth all align. Unlike a total eclipse, in which the Earth casts a cone-shaped shadow, or umbra, that blacks out the moon, the effect of a penumbral eclipse is more subtle, reports Deborah Byrd at EarthSky.com. The face of the moon will slowly darken several shades over time as it passes through the penumbra, the more diffuse area on the edge of the shadow cone.

According to Bruce McClure at EarthSky.com, the ideal spots to view this particular eclipse are in Europe, Africa, Greenland and Iceland and that the entire eclipse will last four hours and 20 minutes. In North America, the period of greatest eclipse will take place at 7:44 P.M. local time. According to McClure, some people will notice the subtle shading but others may not be able to tell the moon is in shadow at all. Anyone hoping for a more showy eclipse will have to wait until August 21, however, when the first total solar eclipse that will be visible from all of the United States will take place for the first time in 99 years.

The second cosmic event taking place on Friday is the Full “Snow” Moon, which lights up the sky every February. Doyle Rice at USA Today explains that the name was given to the moon by Native Americans as part of a system used to keep track of the seasons. He reports that the name Snow Moon is pretty apt, since on average February is the snowiest month in the United States. There’s also an alternate name, according to The Old Farmer’s Almanac; it's also called the Full Hunger Moon because tough weather made hunting difficult during this time of year.

Anyone not too tuckered out by watching the eclipse can try and wait up (or get up early) for the third event, a flyby of comet Comet 45P/Honda-Mrkos-Pajdušáková—the so-called New Year Comet. Weather.com reports that the comet will be visible with binoculars in the predawn hours when it passes through the constellation Hercules.

Its three names come from the astronomers who discovered it in 1948, writes Irene Klotz at Seeker, and it will pass 7.4 million miles from Earth. This is closer than the last time it appeared in 2011, making it the eighth closest comet to buzz our planet since tracking began in 1950, Klotz reports.

The comet is unusual in other ways as well. It has a beautiful emerald green color, likely caused by the evaporation of diatomic carbon. And Spaceweather.com reports that early incoming glimpses of the comet show it has undergone some changes since observers last saw it. It’s three times dimmer than expected and it seems to have lost its tail. Spaceweather proposes that when the comet went around the sun inside the orbit of Venus, it burned off too much of its ice core, extinguishing its tail.

Sky and Telescope advises that anyone who misses 45P will have a chance to see another comet using binoculars, C/2015 ER61, when it appears in the sky during mid-April to mid-May.

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