Comet Leonard to be closest to Earth December 12 (earthsky.org)

[eppur_se_muova]

Posted by Eddie Irizarry and Deborah Byrd
December 9, 2021

2021’s best comet

Comet C/2021 A1 (Leonard) is 2021’s best and brightest comet. It’s not visible to the eye alone. But it’s a good binocular comet, in the sky before sunup now for Northern Hemisphere observers, soon to be in the evening sky, too. By late December and January, it should become visible from Earth’s Southern Hemisphere. Comet Leonard is now heading sunward. It’ll sweep closest to Earth on December 12, passing some 21 million miles (34 million km) away. Then six days later – on December 18 – the comet will have an exceptionally close pass of Venus of just 2.6 million miles (4.2 million km). See the charts below. It’ll round the sun at perihelion on January 3, 2022, at a distance of about 56 million miles (0.6 AU, or 90 million km). Comets are typically brightest around perihelion, and the comet has been brightening and is still getting brighter. This month is a great time to look for this marvelous binocular comet!

Astronomer Greg Leonard discovered the comet as 2021 began. Discovery images already showed a tail for the comet, suggesting we might see a nice tail as Comet Leonard draws closer to the Earth and sun. And telescopic observers and astrophotographers do now see a tail, as photos on this page show.

Binocular and online viewing

So, again, Comet Leonard is a good binocular comet now. Ordinary 10×50 binoculars from a discount store is a reasonable way to go. And the comet might be barely detectable with the eye alone, by experienced observers, in dark skies as 2021 draws to a close.

There will be a free, online viewing event for this comet, from the Virtual Telescope Project in Rome, Italy, starting at 11:15 p.m. CST on the night of December 11 (5:15 UTC on December 12; translate UTC to your time). See the poster below, and click here for more info on the live viewing.
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Comet Leonard after sunset

Around December 14-16, 2021, Comet C/2021 A1 (Leonard), if still intact, will become visible just after sunset, very low in the southwest horizon, as seen from the U.S.
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more (incl. charts): https://earthsky.org/astronomy-essentials/comet-leonard-might-become-2021s-brightest-2022/?utm_source=EarthSky+News

[2naSalit]

2. Is there one there?

I haven't been able to see anything at night for weeks due to clouds. Maybe once in a while I catch a glimpse of something in a big enough hole in cloud.

If I have a constellation to hone in on, I can probably find it. Even an astrological sector would help, I can find those too.

[2naSalit]

5. I have some binos

That are like small spotting scopes, 10x42, I just need to know what part of the sky to scan and a time window. My dad was a celestial navigator and he taught how to find stuff in a big sky. I live where there is little to no light pollution, up on a hill, so there's a lot to filter out.

[eppur_se_muova]

4. It's moving fast -- "arc to Arcturus" still works well for a little while ...

Facing east about 45 minutes before sunrise, as seen from North America and similar latitudes. Comet C/2021 A1 (Leonard) is an ultra-fast comet. It’s traveling so fast that its position in our skies will change daily during early December 2021. Here is its location on December 9-11, 2021. The “handle” of the Big Dipper points to the bright, white-yellow star Arcturus. Look for Comet Leonard closer to the horizon. To see the comet, you’ll want a dark sky. Illustration by Eddie Irizarry using Stellarium.

[2naSalit]

6. Thank you!

That's all I need to know! When the clouds blow by, I might catch a glimpse of it.