The comet 46P/Wirtanen will have a “close” encounter with Earth on sunday, December 16. as with all objects in space, close is a relative term.
Comet 46P/Wirtanen will pass by Earth a mere 7.2 million miles away. according to NASA’s jet propulsion Laboratory, this “will reach an estimated naked-eye magnitude of three to 7.5,” so it should be visible without binoculars or telescope, weather and light permitting.
46P/Wirtanen passes near to Earth each 5.4 years. Sunday’s pass will be the tenth nearest the comet has passed close to Earth since 1950. The diameter of the comet is estimated to be 3/4 of a mile wide and moving at a speed of 21,000 miles per hour.
“Although the comet is moving comparatively quickly through our solar system, it’s still moving comparatively slowly in our sky,” says Erin Hicks, professor of astronomy and Director of the UAA Planetarium. “Its motion will be noticeable over the course of a few nights in that its position can shift with respect to the background stars. in a single night the comet’s location will seem to be unchanged and it’ll seem to easily move across the sky along with the stars.”
When the comet is nearest to the earth on Sunday, it’ll be positioned “roughly between the constellation of Taurus and the Pleiades star cluster,” Hicks says.
Astronomy magazine Sky and Telescope says to not get your expectations too high. The comet is a dark object in the sky. The magazine says most of the people who view the comet can “typically describe it as a nearly circular cloud, comparable to or rivaling the Moon in angular size and showing a bit brighter and more condensed close to the center.”
As with viewing meteor showers and the aurora, the key to success on being able to see the 46P/Wirtanen comet is darkness. go away from light pollution and find a completely dark sky. The moon is at its first quarter phase on Sunday, so will cast some extra light in the sky.
46P/Wirtanen was discovered on 17.January.1948 by Carl Wirtanen at Lick Observatory.