Leonids Meteor Shower

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Leonids Meteor Shower


Leonids' Radiant Map

From Wes Stone's Skytour:


Predicted Maximum: November 17, ~21:00 UT (=Nov. 17, 1:00pm PST; Nov. 17, 4:00pm EST)
Moon: New Moon (no interference)

WHEN TO WATCH: The predicted outburst, perhaps with rates of 100-500 Leonids per hour, strongly favors Asian observers, who should watch on the morning of November 18. North American observers should especially try to cover the morning of Tuesday, November 17 in case of unusual activity leading up to this peak. The Moon will be completely out of the picture and will not cause any problems. Just keep radiant elevation in mind wherever you're observing from. The radiant rises between 10pm and midnight for the bulk of the Northern Hemisphere. Leonid activity will be nonexistent before this time, and relatively very low for a couple of hours thereafter. Morning hours tend to produce the best rates, although the few earthgrazing Leonids seen around radiant-rise can be very impressive.

The Leonids are very fast meteors.  The shower is active at a low "background" level for about a week from November 14-21. Quite a few sporadic and minor-shower meteors join the cast, especially in the predawn hours.

From Science@NASA:

Astronomers from Caltech and NASA say a strong shower of Leonid meteors is coming in 2009. Their prediction follows an outburst on Nov. 17, 2008, that broke several years of "Leonid quiet" and heralds even more intense activity next November.

"On Nov. 17, 2009, we expect the Leonids to produce upwards of 500 meteors per hour," says Bill Cooke of the NASA Marshall Space Flight Center. "That's a very strong display."

see captionForecasters define a meteor storm as 1000 or more meteors per hour. That would make the 2009 Leonids "a half-storm," says Jeremie Vaubaillon of Caltech, who successfully predicted a related outburst just a few weeks ago.

On Nov. 17, 2008, Earth passed through a stream of debris from comet 55P/Tempel-Tuttle. The gritty, dusty debris stream was laid down by the Leonids' parent comet more than five hundred years ago in 1466. Almost no one expected the old stream to produce a very strong shower, but it did. Observers in Asia and Europe counted as many as 100 meteors per hour.

Vaubaillon predicted the crossing with one-hour precision. "I have a computer program that calculates the orbits of Leonid debris streams," he explains. "It does a good job anticipating encounters even with very old streams like this one."

The Nov. 17, 2008 outburst proved that the 1466 stream is rich in meteor-producing debris, setting the stage for an even better display in 2009.

On Nov. 17, 2009, Earth will pass through the 1466 stream again, but this time closer to the center. Based on the number of meteors observed in 2008, Vaubaillon can estimate the strength of the coming display: five hundred or more Leonids per hour during a few-hour peak centered on 21:43 UT.

"Our own independent model of the debris stream agrees," says Cooke. "We predict a sub-storm level outburst on Nov. 17, 2009, peaking sometime between 21:34 and 21:44 UT."

The timing favors observers in Asia, although Cooke won't rule out a nice show over North America when darkness falls hours after the peak. "I hope so," he says. "It's a long way to Mongolia."

Many readers will remember the great Leonid showers of 1998-2002. The best years (1999 and 2001) produced storms of up to 3000 Leonids per hour. The 2009 display won’t be so intense. Instead, if predictions are correct, next year's shower could resemble the 1998 Leonids, a "half-storm"-level event caused by a stream dating from 1333. That old stream turned out to be rich in nugget-sized debris that produced an abundance of fireballs. Many observers consider the 1998 Leonids to be the best they've ever seen.

Could 2009 be the same? Vaubaillon expects a similar number of meteors but fewer fireballs. If the models are correct, the 1466 stream in Earth’s path contains plenty of dust but not so many nuggets, thus reducing the fireball count. On the bright side, the Moon will be new next Nov. 17th so nothing will stand in the way of the shower reaching its full potential.

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9 Responses

  1. CY says:


    Being clueless to how astronomy works, I am not sure if I had interpretered the article correctly
    Hope you guys will be able to clarify.

    Does this mean that the meteor shower would peak at 5am on 18 Nov 09 Singapore time?

    Thank you for the clarification.

  2. HELiX says:

    Hi CY,

    Yes, that’s correct. The peak is predicted to be on the morning of 18 November 2009.

    Do note that the Leonids meteor shower occurs over a few days, not just on a particular day. While this meteor shower reaches its peak on 18 Nov, it is still possible to see meteors, just that there is a lower probability, a few days before and after 18 Nov.

    It would be best to watch for meteors between midnight to sunrise, although that is no guarantee of being able to see meteors, due to Singapore’s skies being heavily light-polluted. If you would like to meet others who are also fascinated by celestial events such as meteor showers, I would encourage you to attend the two Leonids events as advertised on our website.

    I hope this helps, and good luck with it!

  3. jax says:

    Hi, what are the 2 leonids events?

  4. HELiX says:


    The two events are the Leonids Meteor Shower Gazing and Camp Leonids.

    Leonids Meteor Shower Gazing – http://astronomy.sg/archives/563
    Camp Leonids – http://astronomy.sg/archives/561

    Please kindly refer to our Calendar page for an overview of the events.

    Thank you!

  5. star17 says:


    just asking. do we need to have special equipment, like binoculars, to be able to see the shower clearly? &from east coast.wil the lights from the ships etc interfere w the interfere with the viewing?

  6. Stan says:


    Will there be any recommended spots to view the meteor shower?

  7. CK says:

    hey, what is the estimated time that the first meteor will be seen?

  8. Derek says:

    Hi all,

    Special equipment will not be needed for seeing meteors. They can be seen with the unaided eye quite clearly.

    The lights from the ships may interfere with the sky condition nearer to the horizon only. I believe that this will not affect the meteors much.

    I recommend that you can try to catch the event at the Japanese Gardens, as the event also falls on the peak of the meteor shower. Generally, dark skies with no obstructions (like HDB buildings) are very suitable for meteor gazing.

    We cannot tell when the first meteor will be seen. In fact, scientists cannot predict when the individual meteors will appear. They are quite random, and will occur over a few hours, even days. However, do note that meteors are more likely to appear after midnight due to the Earth’s rotation.

    Enjoy the meteor shower!

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