Astronomy Essentials

Leonid meteor shower peaks morning of November 17, in moonlight

Star chart of constellation Leo with radial arrows indicating source of Leonid meteor shower.
Regulus, the brightest star in the constellation Leo the Lion, dots a backwards question mark of stars known as the Sickle. If you trace all the “shooting stars” from the Leonid meteor shower backward, they appear to radiate from this area of the sky.

2021’s Leonid meteor shower

November’s Leonid meteor shower is known for periodic storms of historic proportions, when shooting stars fall like rain. In 2021, this meteor shower is due to peak Wednesday morning, November 17. But the moon is in a waxing gibbous phase. It will hang around most the night, brightening the sky and washing out most of the meteors. There will be only the briefest of intervals between moonset and the onset of morning dawn Wednesday morning. What to do?

You can try watching for the meteors in moonlight. You won’t see as many as you would in a year with no moon. But you might see a particularly bright Leonid or two streaking across the sky.

Or try that brief interval between moonset and dawn. Remember, when the moon is low in the sky – say, for half an hour to an hour before it sets – its glare will be reduced. If you’re going this route, watching shortly before dawn Wednesday, don’t be afraid to start watching when the setting moon is still in the sky. Visit Sunrise Sunset Calendars and check the astronomical twilight and moonrise and moonset boxes to learn these key elements.

Whatever you do – as always, to increase your chances – be sure to watch from a rural, dark sky location.

See the moon phase for every day in 2022 on EarthSky’s lunar calendar. Available now! Guaranteed to sell out, so get one while you can.

Leonid's meteor shower. The meteor emitted a bright flash with a little popping noise
View at EarthSky Community Photos. | Mike Baxter in Arkansas, United States, captured this meteor on November 16 and wrote: “We were staying in Buffalo Outdoor center’s Mountain Ecstasy cabins in Compton Arkansas. Woke up at 4am to watch the Leonid’s meteor shower and captured this bright beauty enter the atmosphere. It emitted a bright flash with a little popping noise, amazing!” Thank you, Mike!
Round overexposed moon and long thin white streak in lightly starry sky.
This isn’t a Leonid meteor. It’s an Orionid. But – as this photo shows – you can sometimes catch a meteor in moonlight, assuming the meteor is bright enough. Photo taken in late October 2016 by Eliot Herman in Tucson, Arizona. Thanks, Eliot!
Two thin green horizontal streaks in starry sky.
View larger to see the colors better. | Another photo from Eliot Herman in Tucson, Arizona. This is a double Leonid meteor, captured 2 days before the peak of the shower in 2018. Eliot commented, “The Leonids are the greenest meteors I see.” And he has seen a lot of meteors!

How many Leonid meteors will you see in 2021?

The answer always depends on when you watch, where you watch, and on the clarity and darkness of your night sky.

In ideal conditions (a rural location and a moon that’s absent from the sky) you can see from 10 to 15 meteors an hour at the peak of the shower. In 2021, we have to deal with a waxing gibbous moon, which will make it hard to see fainter meteors. The best time to look is just before dawn after the moon has set, but that interval will be brief.

By the way, while no Leonid storm is predicted for 2021 – and while moonlight will wash out most of the meteors you’d otherwise have seen – you can still catch plenty of Leonid meteors from November 6 to 30. That’s when Earth is plowing through the orbital path of Comet 55P/Tempel-Tuttle. The comet itself is far away. But comets litter their orbits with bits of debris. These bits of dust smack into Earth’s atmosphere each year at this time. They vaporize, creating the streaks of light across a dark night sky that we know as meteors.

12 small objects streaking toward Earth viewed from orbit in black and white.
Leonid meteors, viewed from space in 1997. Image via NASA.

Where should I go to watch?

We hear lots of reports from people who see meteors from yards, decks, streets and especially highways in and around cities. But the best place to watch a meteor shower is always in the country. Just go far enough from town that glittering stars, the same stars drowned by city lights, begin to pop into view.

Find a place to watch at EarthSky’s Best Places to Stargaze page.

City, state and national parks are often great places to watch meteor showers. Search online for the name of your state or city with the words city park, state park or national park. Then, be sure to go to the park early in the day and find a wide open area with a good view of the sky in all directions. Also, make sure the park is open after dark!

Like most (but not all) meteor showers, the Leonids are typically best after midnight. When night falls, you’ll probably be impatient to see meteors. But you’ll see that bright moon in the sky. And evening is not the best time to catch Leonids. If you do plan to watch in moonlight in 2021, at least wait until after midnight. Catch a nap in early evening if you can. After midnight, lie back comfortably and let your gaze wander across all parts of the sky. Until just before dawn, the moon will be blazing! You might feel as if you’re bathing in the light of the moon. That experience, in itself, can be transformative … even if you don’t see any meteors!

Sometimes friends like to watch together, facing different directions. When somebody sees one, they can call out meteor! Then everyone can quickly turn to get a glimpse.

Which direction should I look to see the Leonids?

Meteors in annual showers get their names from the point in the starry sky from which they appear to radiate. This shower’s name comes from the constellation Leo the Lion, because these meteors radiate outward from the vicinity of stars representing the Lion’s Mane.

If you trace the paths of Leonid meteors backward on the sky’s dome, they do seem to stream from near the star Algieba in the constellation Leo. The point in the sky from which they appear to radiate is the radiant point. This radiant point is an optical illusion. It’s like standing on railroad tracks and peering off into the distance to see the tracks converge. The illusion of the radiant point comes from the fact that the meteors – much like the railroad tracks – are moving on parallel paths.

In recent years, people have gotten the mistaken idea that you must know the whereabouts of a meteor shower’s radiant point in order to watch the meteor shower. You don’t need to. The meteors often don’t become visible until they are 30 degrees or so from their radiant point. They are streaking out from the radiant in all directions.

Thus, the Leonid meteors – like meteors in all annual showers – will appear in all parts of the sky.

Etchings of meteors over Niagara Falls and a scene with people looking up at meteors.
Old woodcuts depicting 1833 Leonid meteor storm – “the night the stars fell.”

A history of meteor storms

Scientists don’t expect a Leonid meteor storm in 2021. Most astronomers say you need more than 1,000 meteors an hour to consider a shower a storm. That’s far from the 10 to 15 meteors per hour the Leonids deliver in average years.

The Leonid shower is famous for producing meteor storms, though. The parent comet, Tempel-Tuttle, completes a single orbit around the sun about once every 33 years. It releases fresh material every time it approaches the sun. Since the 19th century, skywatchers have looked for Leonid meteor storms about every 33 years, beginning with the meteor storm of 1833, which witnesses said produced more than 100,000 meteors an hour.

The next great Leonid storms were about 33 years later, in 1866 and 1867. In 1899, a meteor storm did not materialize. Not until 1966 did the next spectacular Leonid storm occur, this time over the Americas. In 1966, observers in the southwest United States reported seeing 40 to 50 meteors per second (that’s 2,400 to 3,000 meteors per minute) during a span of 15 minutes on the morning of November 17, 1966.

In 2001, another great Leonid meteor storm occurred. Spaceweather.com reported:

The display began on Sunday morning, November 18, when Earth glided into a dust cloud shed by Comet Tempel-Tuttle in 1766. Thousands of meteors per hour rained over North America and Hawaii. Then, on Monday morning November 19 (local time in Asia), it happened again: Earth entered a second cometary debris cloud from Tempel-Tuttle. Thousands more Leonids then fell over east Asian countries and Australia.

View SpaceWeather’s 2001 Leonid meteor gallery.

Thin white almost vertical streak over dark, distant hilly horizon.
James Younger took this photo during the 2015 Leonid meteor shower looking over the San Juan Islands in the Pacific Northwest.

The Leonid meteor shower of 1833

Sky filled with very, very many falling stars and 1830s people out looking up.
The night the stars fell. Engraving by Adolf Vollmy (1889). Image via Wikimedia Commons.

Adolf Vollmy produced this famous engraving of the 1833 Leonid meteor shower for the Adventist book “Bible Readings for the Home Circle.” It’s based on a painting by Swiss artist Karl Jauslin, which, in turn, was based on a first-person account of the 1833 storm by a minister, Joseph Harvey Waggoner, who saw the 1833 shower on his way from Florida to New Orleans.

In that famous shower, hundreds of thousands of meteors per hour fell. It was the first recorded meteor storm of modern times.

Many colorful streaks of light in sky above a waterfall.
Artist’s illustration of the Leonid meteor shower in 1833, one of the most spectacular in history. Image via NJ.com/ Edmund Weiss.

Bottom line: The peak of the 2021 Leonid meteor shower occurs between the evening of November 16 and dawn on November 17. The waxing gibbous moon will interfere, brightening the sky.

EarthSky’s meteor shower guide for 2021

Planet-observing is easy: Top tips here

EarthSky’s monthly planet guide: Visible planets and more

Posted 
November 16, 2021
 in 
Astronomy Essentials

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