Today's comet webcast is one of two by the Virtual Telescope Project (the other airs December 16, also at 5 p.m. EST), because, according to the project's director astrophysicist Gianluca Masi, this is when the comet will be close to its maximum brightness. Writing for Sky & Telescope, Joe Rao warns, "Even for those who are blessed with dark and starry skies, finding the comet could prove to be a bit of a challenge". It was closest to the sun on December 12.
Don't expect to see the comet's tail.
The comet was discovered by Carl Alvar Wirtanen on January 15, 1948 at Lick Observatory in California. Look up with a pair of binoculars between twilight and sunrise. The Virtual Telescope Project will be live streaming the comet's visit at 5 p.m. EST. That simply makes the comet much easier to find, if you are not accustomed to using a star chart. It has a diameter of about three-quarters of a mile - a relatively small comet. But the comet is an interesting object of study and helps astronomers better understand comets in general, especially those that are a part of the Jupiter family. The comet will melt a little as it passes the sun, giving off a cloudy green hue. That's what creates the glowing green cloud. The comet is now well up in the southern sky around 10 p.m., but may be seen in the southeastern sky earlier in the evening.
Farnham oversees an online clearinghouse of information about the comet that educates the public and encourages collaboration among astronomers who gather data about it.More news: Israeli military finds 4th Hezbollah tunnel from Lebanon
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Comet 46P was originally chosen by the European Space Agency to land the Rosetta probe on its surface, but launch delays caused a new target to be selected.
"The fuzziness is just because it's a ball of gas basically", Tony Farnham, a research scientist in the astronomy department at the University of Maryland, said Saturday morning after a long night studying the comet at the Discovery Channel Telescope, about 40 miles southeast of Flagstaff, Arizona. The fact is, most comets are not at all spectacular in those terms.
Bodewits said this sky-watching event will provide important context to the Rosetta and Deep Impact missions.
"We're getting a look at stuff that was formed during the formation of the solar system and has been out in the deep freeze since then", Lattis said to CNN. "When these things come in and we get a chance to study them, we're seeing some of the raw materials out of which the Earth and the other planets and everything else formed".