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April's Lyrid Meteor Shower

The oldest known meteor shower peaks this year on April 22

Apr. 21, 1999: Stargazers in recent months may have noticed something missing from the nighttime sky: shooting stars. Each year between January and April there is a lull in meteor activity as Earth passes through a part of its orbit that is free from major cometary debris streams. Without much space dust in the area, there are simply fewer cosmic particles burning up in the atmosphere to produce visible shooting stars.

Above: Artist Duane Hilton created this nighttime painting of a Lyrid meteor streaking over sand dunes in Death Valley, CA.

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It's been a long 3 months for meteor enthusiasts, but the 1999 intermission in meteor activity is nearly over. It ends this Thursday with the arrival of the annual Lyrid meteor shower. The Lyrids will peak at 1600 UT (9 a.m. Pacific Standard Time) on April 22 with at least 10-20 meteors per hour. The predicted peak occurs during daylight on Thursday morning across most of the United States, but the rate of meteors should still be high a few hours earlier before the sun rises. No matter where you live, the best time to look will be during the hours before dawn on Thursday after the waxing quarter Moon has set. Typical Lyrid meteors are nearly as bright as the main stars in the Big Dipper, which makes it a good shower for both beginning and experienced observers.

Most years, observers of the Lyrids can expect to view one or two shooting stars every few minutes. That's just a trickle compared to the avalanche of shooting stars and fireballs seen by millions during the 1998 Leonids meteor shower, but the Lyrids are not always so meek. In 1982, for example, over 90 meteors per hour were seen for a brief time. An even bigger outburst in 1803 was documented by a journalist in Richmond, Virginia who wrote:

"Shooting stars. This electrical phenomenon was observed on Wednesday morning last at Richmond and its vicinity, in a manner that alarmed many, and astonished every person that beheld it. From one until three in the morning, those starry meteors seemed to fall from every point in the heavens, in such numbers as to resemble a shower of sky rockets..." [ref]

Another account quoted an observer who "counted 167 meteors in about 15 minutes, and could not then number them all." [ref]

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Although the Lyrids are not usually so spectacular, they are notable as the oldest recorded meteor shower. Lyrids have been observed for at least 2600 years, according to Chinese records from 687 BC describing "stars that fell [like] rain."

The Lyrid meteor stream is asscociated with periodic comet Thatcher C/1861 G1, whose orbit is tilted nearly 80 degrees with respect to the plane of the solar system. Because the comet spends most of its time well away from the planets, it is nearly immune to significant gravitational perturbations. This is probably the reason why the debris stream has remained stable and the Lyrid shower has been observed for so many centuries.

How to View the Lyrids

Lyrid meteors can be seen anytime after midnight when the constellation Lyra is well above the horizon. The best time to look is between about 3 a.m. and dawn. That's when the local sky is pointing directly into the meteoroid debris stream (see the diagram below). The early morning hours of April 23 and April 24 should be good times to watch no matter where you live.

Above:The rate of meteor activity is usually greatest near dawn because the earth's orbital motion is in the direction of the dawn terminator. Earth scoops up meteoroids on the dawn side of the planet and outruns them on the dusk side.

Lyrids at a Glance The meteor shower is active from Apr. 16 until April 25. Maximum activity is expected at 1600 UT on Apr 22, 1999. The radiant is at RA=18h06m, DEC=+33o Atmospheric velocity=49 km/s Average magnitude 2.4 Current Moon Phase   Updated every 4 hours.

The constellation Lyra, pictured in the sky map below, rises at approximately 11:00 p.m. local time at mid-latitudes in the Northern hemisphere. The radiant of the shower is located near Vega, a hard-to-miss zeroth magnitude star. Vega is well-known as a member of the "Summer Triangle" of bright stars which also includes Deneb and Altair. To find Lyra at 2:00 a.m., go outside and face north-northeast. Vega will appear approximately 50 degrees above the horizon between the constellations Cygnus and Hercules.

You won't need binoculars or a telescope to observe Lyrid meteors, the naked eye is usually best for seeing meteors which often streak more than 45 degrees across the sky. The field of view of most binoculars and telescopes is simply too narrow for good meteor observations.

Experienced observers suggest the following viewing strategy: Dress warmly. Bring a reclining chair, or spread a thick blanket over a flat spot of ground. Lie down and look up somewhat toward the north. Meteors can appear in any part of the sky, although their trails will tend to point back toward the radiant, pictured in the sky map below)

The image indicates the general region of the sky from which the Lyrid meteors appear to emanate (red dot). This point, called the radiant, is really an optical illusion - the meteors are moving along parallel paths, but appear to come from a single point, just as a stretch of parallel railroad tracks will appear to meet at a point on the horizon. Web Links

The Lyrids - From Gary Kronk's Comets & Meteors Web Site

North American Meteor Network - April 99 Newsletter featuring information about the Lyrids

North American Meteor Network - home page

Leonids Live! -site of the live webcast of the 1998 Leonids

Related Stories:

A Wild Ride to the Stratosphere in Search of Meteors -- Apr. 14, 1999. The payload from the NASA Meteor Balloon has been recovered.

Meteor Balloon set for Launch -- Apr. 9, 1999. NASA scientists prepare to launch a weather balloon designed to capture micrometeoroids in the stratosphere.

Leonid Sample Return Update -- Apr. 1, 1999. Scientists will describe initial results from a program to catch meteoroids in flight at the NASA/Ames Leonids Workshop April 12-15, 1999.

The Ghost of Fireballs Past -- Dec. 22, 1998. RADAR echoes from Leonid and Geminid meteors.

Bunches & Bunches of Geminids -- Dec. 15, 1998. The Geminids continued to intensify in 1998

The 1998 Leonids: A bust or a blast? -- Nov. 27, 1998. New images of Leonid fireballs and their smokey remnants.

Leonids Sample Return payload recovered! -- Nov. 23, 1998. Scientists are scanning the "comet catcher" for signs of Leonid meteoroids.

Early birds catch the Leonids -- Nov. 19, 1998. The peak of the Leonid meteor shower happened more than 14 hours earlier than experts had predicted.

A high-altitude look at the Leonids -- Nov. 18, 1998. NASA science balloon catches video of 8 fireballs.

The Leonid Sample Return Mission -- Nov. 16, 1998. NASA scientists hope to capture a Leonid meteoroid and return it to Earth.

Great Expectations: the 1998 Leonid meteor shower -- Nov. 10, 1998. The basics of what the Leonids are and what might happen on November 17.

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For more information, please contact: Dr. John M. Horack , Director of Science Communications

Author: Dr. Tony Phillips Curator: Bryan Walls NASA Official: John M. Horack

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• Astrophysics