Comet 46P/Wirtanen is 2018’s brightest comet, but that doesn’t mean it’s bright. Although theoretically visible to the eye now, the comet is large and diffuse … not easy to see. Charts, tips and other info here.
Have you heard about comet 46P/Wirtanen? It’s due to pass closest to the sun on December 12, 2018, and closest to Earth just a few days later, on December 17. Comet Wirtanen is the brightest comet in the night sky now; it’s the brightest comet of 2018. Although theoretically visible to the eye now, this comet is not easily visible to the eye. Astronomers have captured it using telescopes and binoculars (see a collection of photos here). It’s best seen from a dark location. To glimpse it, check to see if your local astronomy club will be hosting events for observing comet 46P/Wirtanen. Or visit the Virtual Telescope Project for a free, online viewing of comet Wirtanen on December 12 and 17.
Want to try to spot the comet yourself, in a dark sky? Keep reading …
As of early December, observers around the world are reporting that Comet 46P/Wirtanen is, in theory, bright enough to be seen with the eye. The problem is that the dim light reflected from the comet is spread over a large cometary atmosphere, or coma.
So you’ll be looking for a large, diffuse, dim object.
The comet is moving in front of the stars from one night to the next. It appears in front of the same stars as seen from both the Northern Hemisphere and the Southern Hemisphere. But, as always, your orientation on these stars is different from different parts of Earth. Where should you look on any given date? See the charts below.
Or, try setting your specific location to this comet Wirtanen page at In-the-Sky.org.
You can also set your location at this site: TheSkyLive’s comet Wirtanen page.
Here’s another helpful article on how to see the comet, from SkyandTelescope.com.
Here’s a Northern Hemisphere view showing the night of December 15, 2018, when the comet will be closest. Face east, shortly after nightfall. Note that the comet is approximately on a line between the bright star Aldebaran, in the V-shaped face of the Bull in Taurus, and the Pleiades star cluster. Illustration by Eddie Irizarry using Stellarium.
From Earth’s Southern Hemisphere, you’ll find the comet set against the same stars and constellations, but your orientation on them will be different. This chart is for December 17, 2018 – when the comet is closest – as seen from Adelaide, Australia. Face northeast after nightfall. Note that the comet is approximately on a line between the bright star Aldebaran and the Pleiades star cluster. Chart via AstroBlog by Ian Musgrave, which has more info for Southern Hemisphere viewers wishing to see the comet.
The comet is still approaching, and so it is getting brighter. It should be brightest around December 17, when it will pass closest to Earth, within 7.4 million miles (12 million km). At that time, its visual magnitude should be around 3 (some are saying closer to 4, which would mean the comet is fainter).
If it the comet were a point source, like a star, it would be of medium brightness! But its diffuse coma and the nearly full moon on December 17th will make observations challenging.