Less than a year ago, when Comet Leonard was first discovered, it was still an incredibly dim and obscure chunk of rock traveling out near the orbit of Jupiter.
Now it has reached our neighborhood of the solar system on its journey toward the sun and is being billed as the brightest comet of the year.
Here's how to see it:
"The comet is in the early morning sky right at the moment, and that means getting up very early, probably around 5 a.m. or so and looking more or less to the northeast," Ed Krupp, an astronomer and the director of the Griffith Observatory in Los Angeles, tells NPR.
For people in North America, the best time will probably be Monday morning — weather permitting — when the comet will be near Arcturus, low on the horizon. The star is in the constellation Boötes (the Herdsman). There's an easy way to find it: Follow the curve of the Big Dipper (in Ursa Major) out past the end of the handle. The next bright star you see will be Arcturus. A good memory aid is to remember that from the Dipper handle, you "arc to Arcturus."
"The comet will just be about half the width of a clenched fist to the left" of Arcturus, Krupp says. "You might spot it with the unaided eye, but more likely, you're going to need binoculars [or] a telescope."
Exactly how bright a comet will appear to observers on Earth can be difficult to determine, and often a matter of intense speculation among amateur and professional astronomers alike. Leonard is no different.
But for people who saw the Neowise comet in the summer of 2020, Leonard might be something of a disappointment, says Peter Veres, an astronomer at the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics.
"I wouldn't say this comet will be spectacular if you compare it to Comet Neowise," Veres tells NPR.
He says Leonard might be visible with the naked eye, but "you will need to be in a dark environment, far from the city."
If you miss it in the morning, you'll get another chance in the evening later in the month, Krupp says.
"The optimum time [in the evening] probably is from the Dec. 17 on," he says.
This time, look for the planet Venus to the southwest. The planet is the brightest object in the sky after the sun and moon. The comet will be between Venus and the horizon.
After that, things get a bit more challenging for Northern Hemisphere observers. They will need to book a flight to somewhere in the Southern Hemisphere next month. Australia anyone?
But after Leonard leaves the southern skies behind, you'll be completely out of luck. With an orbital period of 80,000 years, the last people on Earth to have witnessed the comet were our distant ancestors — both Neanderthal and Homo sapiens.
And, we'll be the last humans to ever glimpse it from this vantage point. Because of the shape of Leonard's orbit, the comet is set to be kicked out of the solar system sometime after its Earthly flyby.
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