Comet Leonard still might become 2021’s brightest

Comet Leonard (C/2021 A1 Leonard) photographed on October 29, 2021, by Michael Jager (@komet123jager on Twitter) from Austria.

Comet Leonard is brightening

Exciting news! A much-anticipated comet is brightening and still might become 2021’s brightest comet. Astronomer Greg Leonard discovered the comet that now bears his name – C/2021 A1 (Leonard) – on January 3, 2021, at the Mount Lemmon Observatory in Arizona. Astronomers reported then that discovery images showed a tail for the comet, suggesting we might see a nice tail as Comet Leonard draws closer to the Earth and sun. The comet is now between the orbits of Mars and Earth, heading inward. Comets are typically brightest around the time they’re closest to the sun. And Comet Leonard will reach perihelion, its closest point to the sun, around January 3, 2022.

And what about the comet’s closest approach to Earth? NASA/JPL estimates that Comet Leonard’s closest approach to Earth will be on December 12, 2021, at around 13:54 UTC. It’ll pass Earth at the extremely safe distance of 21,687,279 miles (34,902,292 km).

Its orbit also suggests that the comet will then pass relatively close (about 2,632,000 miles) to planet Venus on December 18, 2021.

Estimates indicate it might reach a visual magnitude between 5 and 2.6 (the lower the brighter), and although at its brightest the comet will be close to the horizon, we still might get very good views using binoculars during the days before closest approach to Earth, in early December 2021. Visibility to the eye alone may still be a possibility.

Nature provides us with sky events seen once in a lifetime. Comet Leonard might be one of these, as preliminary observations suggest this comet completes an orbit around the sun in about 80,000 years.

In other words, after this current close sweep past our sun, we will not see Comet Leonard again.

EarthSky’s 2022 lunar calendars are available now! We’re guaranteed to sell out, so get one of these beautiful calendars while you can. Your support helps EarthSky keep going!

View at EarthSky Community Photos. | Eliot Herman in Mayhill, New Mexico, captured this photo of Comet Leonard and a spiral galaxy on October 30, 2021. He wrote: “Comet Leonard (C/2021 A1) is predicted to put on a nice show in a little more than a month. At present it is still faint at about magnitude 11, and on October 30 it had a very close conjunction with galaxy NGC 3897 in Ursa Major.” Thank you, Eliot!

Will you see this comet?

This comet is initially visible from the Northern Hemisphere. But it will become visible from the Southern Hemisphere in December 2021 and January 2022.

Will Comet Leonard be visible to the unaided eye? It’s possible. This might be this year’s brightest comet and will provide a nice spectacle to observers using long exposure cameras, or even binoculars and the smallest telescopes.

An amazing feature of this celestial visitor is that it’s an ultrafast comet. It’s traveling at 158,084 miles per hour (254,412 km/h or 70.67 km per second) relative to Earth.

Despite its incredible speed through the vast space of our solar system, don’t expect to see this comet swoosh across the sky. Like planets, comets do move in front of the star background, but only very slowly due to the large distances involved. Observers using telescopes will have to take a close look at the comet’s position relative to background stars. Then compare the view five or 10 minutes later to detect its motion, because its great distance will cause it to appear as a very slow moving object.

Here are a few charts …

Comet Leonard before sunrise

On November 19, 2021, around 3 am ET, Comet C/2021 A1 (Leonard) passes close to where we can see galaxy NGC 4395 and other faint galaxies using a telescope. Illustration by Eddie Irizarry/ Stellarium.

On November 24, 2021, around 2 am ET, Comet C/2021 A1 (Leonard) will pass very close to where observers using a telescope can spot well known “Whale Galaxy” (NGC 4627), with one caveat: the view will be somewhat close to the horizon at 18 degrees or less. Illustration by Eddie Irizarry/ Stellarium.

Location of Comet Leonard on November 30, 2021, about one hour before sunrise. By this date, the celestial visitor should be an easy target using binoculars. Comet Leonard will be located between the moon (on right, illuminated just around 19%) and the Big Dipper (upper left), facing East before sunrise. Illustration by Eddie Irizarry/ Stellarium.

Location of Comet C/2021 A1 (Leonard) on December 1, 2021. This chart is as seen from U.S., facing east about 90 minutes before sunrise. The Big Dipper asterism in the constellation Ursa Major the Great Bear will provide a good reference for observers to locate the comet. Binoculars should provide a nice view. Illustration by Eddie Irizarry using Stellarium.

Have a telescope? Point it to globular cluster Messier 3 on December 3, 2021, just before sunrise, and you will be able to see Comet C/2021 A1 (Leonard) just below this cluster on that date. Image from Adam Block/ Mount Lemmon SkyCenter.

Comet C/2021 A1 is traveling so fast that its position in our skies will change daily during early December 2021. Here is its location on December 5, 2021, about 90 minutes before sunrise. Comet Leonard will be located very close to where we see bright star Arcturus, as seen here. Facing east, as seen from U.S. Illustration by Eddie Irizarry using Stellarium.

Location of Comet C/2021 A1 (Leonard) on December 10, 2021. By then, it will be brighter but closer to the horizon, as seen from the U.S. about 30 minutes before sunrise. Illustration by Eddie Irizarry, using Stellarium.

Comet Leonard after sunset

Around December 14-16, 2021, Comet C/2021 A1 (Leonard) will become visible just after sunset, very low in the southwest horizon, as seen from the U.S.   

Location of Comet C/2021 A1 (Leonard) on December 15, 2021, about 30 minutes after sunset, facing southwest as seen from the U.S. Illustration by Eddie Irizarry using Stellarium.

On December 17, 2021, about 30 minutes after sunset, comet Leonard will be located below planet Venus. Visible to the unaided eye? Perhaps …  Facing southwest, as seen from the U.S. Illustration by Eddie Irizarry using Stellarium.

December 19, 2021, about 30 minutes after sunset.  facing southwest, as seen from U.S. Illustration by Eddie Irizarry using Stellarium.

This perspective on Comet C/2021 A1 (Leonard) shows its trajectory through our solar system. North is up. You can see that its orbit will cause it to be initially visible from Earth’s Northern Hemisphere, and then from the Southern Hemisphere. Chart via Dominic Ford’s In-the-Sky.

Bottom line: Comet C/2021 A1 (Leonard) – discovered on January 3, 2021 – is heading inward toward its January 3, 2022, perihelion. It might become the brightest comet of 2021! Bookmark this post. We’ll be updating it.

The post Comet Leonard still might become 2021’s brightest first appeared on EarthSky.