Ran Across This on The Old Farmer’s Almanac, Did you know we have a comet coming the 16th?




Comet 46P/Wirtanen is 2018’s brightest comet and comes closest to Earth on December 15–16, 2018—this weekend! As awesome as they can be, you can’t trust comets. We can always predict where they’ll be, but not how they will react with the Sun’s energy. So, the question is: Will it be an amazing sight or another bust?

For a short background, Comet 46P/Wirtanen is indeed the brightest comet in the night sky, though it’s been too faint to see with the naked eye thus far.  From dark sky sites, however, it could just become naked-eye visible soon as it comes closest to Earth on its 5.4-year-long looping orbit.


  • We’ve had a goodly number of busts, such as comet Ison a few years ago that was touted as “The comet of the Century” but never got bright at all.
  • On the other hand, we’ve had two spectacular comets since the mid-70s—the pre-dawn mind-blower Comet West in March of 1976, and then Hale Bopp, which remained brilliant for almost an entire year, mostly in 1997.
  • We’ve also had a bunch of visible-but-not-brilliant comets in the form of Comet Kohoutek in 1973,  Comet Iras-Iraki-Alcock in 1983, Halley in the autumn of 1985, and Hyakutake in 1996. The new one is comet Wirtanen.


This is a good news / bad news kind of deal.

  • The bad is that it’s an unusually tiny comet whose nucleus is just ½ mile wide.
  • The good news is that on December 15 and 16 it will pay Earth its closest-ever visit. It’ll pass just seven million miles from us.  I’ve been watching it through binoculars the past few nights, and think it will brighten to be visible to the naked eye for those in rural regions. It’s doubtful whether it will become bright enough to appear in the glowing skies over cities, although you never know. It should be large and blobby looking, appearing as a fuzzy glob the size of the full moon.


My suggestion is to look halfway up the southern sky starting around 10 p.m. beginning tonight or the next clear night.

If you can recognize the famous Seven Sisters star cluster, also known as the Pleiades—to the upper right of Orion—look far below it and sweep binoculars there, looking for a big blob.  The comet will be brightest on the nights of Saturday, December 15 and Sunday, December16,  when it will be located just left of the Pleiades.

If you don’t already know the Pleiades,  this is a good time to make their acquaintance.  At 10 p.m. any night, look south and you’ll easily see a small, tightly packed group of stars.  That’s it.  Sweep binoculars over them and you’ll be thrilled, since the six naked-eye stars in the cluster will gloriously multiply to dozens, and their blue-white diamond color will be obvious too.  It’s the very best celestial target for binoculars. And once you’ve located this marvelous sight, you’ll know where to look for the comet on December 15 and 16.



Welcome to “This Week’s Amazing Sky,” the Almanac’s blog on stargazing and astronomy. Bob Berman, longtime and famous astronomer for The Old Farmer’s Almanac, will help bring alive the wonders of our universe. From the beautiful stars and planets to magical auroras and eclipses, he covers everything under the Sun (and Moon)! Bob, the world’s mostly widely read astronomer, also has a new weekly podcast, Astounding Universe!

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