Leonid meteor shower: how and when to observe the summit

Sky watchers around the world could get the chance to witness a celestial spectacle this week as the annual Leonid meteor shower reaches its peak.

The Leonids are expected to peak at 1 p.m. ET on Monday, according to EarthSky. You can start seeing meteors on Sunday at 11 p.m. local time, when the constellation Leo rises on the horizon. But it’s best to watch for them between 4 a.m. Monday and sunrise local time, said Robert Lunsford, fireball reporting coordinator for the American Meteor Society.

“Unlike many meteor showers, the Leonids have a very sharp peak,” Lunsford said, adding that there is only one good night to view them.

The Leonids’ parent comet, 55P/Tempel-Tuttle, owes this brief duration. The size of the comet’s debris trail is small, so the Earth passes through it for a short time.

The meteors you see around 11 p.m. Sunday will be Earth grazers, Lunsford said, meaning they will last longer than normal and pass through much of the sky. “But you won’t see as much because much of the Leonid activity will take place below the horizon,” he added.

On a clear day, you can expect to see 10 to 15 meteors per hour.

Showers and thunderstorms

While a meteor shower is expected this year, the Leonids are known to occasionally produce huge meteor storms, with at least 1,000 meteors per hour.

The last Leonid meteor storm was in 2002. However, one of the most memorable storms occurred in 1966, when “we passed right over the center of one of the Leonid streams and the rates were estimated at 40 meteors per second,” Lunsford said.

This storm had such widespread meteor activity in the sky that the meteors appeared to fall like rain.

High meteor activity coincides with when comet 55P/Tempel-Tuttle reaches perihelion – its closest approach to orbiting the sun. It takes 33 years for the comet to orbit the sun, so the largest Leonid meteor showers – and sometimes storms – tend to occur about every 33 years.

For a storm to occur, Earth must pass through a dense portion of comet debris at perihelion, but sometimes our planet only skims the periphery.

The next downpour to coincide with the comet’s orbital cycle will be in 2033, but it is not expected to be a storm, Lunsford said. “We might see speeds of around 100 per hour, which is comparable to the Geminids,” he said, “but we certainly don’t expect storms reaching 1,000 meters per hour.”

Here are the peak dates for the two remaining meteor showers expected this year, according to the American Meteor Society and EarthSky.