Saturday, April 21, 2007

Lyrid Meteor Shower

Also called the April Lyrids, meteors from this shower may be visible from April 19 through 25 with the peak (or maximum) normally on April 21/22. The meteors have an irregular rate, but average 12 to 15 per hour. They appear to originate (or radiate) from a point in the constellation of Lyra (Right Ascension 18 hours 16 minutes, Declination +34°) near the bright star Vega. Appearances of this shower have been traced back over 2,500 years. The parent of this shower is Comet Thatcher, 1861 I. The earliest record of the Lyrid shower is from 687 BC.

This year the Lyrid meteor shower is predicted to peak around 6 pm eastern time on April 22. This will be good for Asia, but North America will be in daylight at that time. Still, the shower’s hourly rate around the time of maximum should be at least half as strong as the peak, so observers in North America should catch the rate as it rises in the early-morning hours of April 22 (at least 10 per hour) and as it falls in the early-morning hours of April 22 (again, at least 10 per hour).

Lyrid Meteor Shower History

March 27, 15 BC - A spectacular Lyrid meteor storm was observed. One observer recorded that the "stars fell like rain."

April 20, 1803 - A brilliant Lyrid meteor shower was seen, though an hourly rate of the meteors was not recorded.

April 21, 1922 - A fair display of the Lyrid meteor shower was seen, though an actual hourly rate of meteors is not known.

Observing Meteors

Usually more meteors are seen near midnight and in early mornings, because during that time our part of Earth is facing in the direction of our orbital path, and we are heading into the meteor swarms. Best observing conditions occur with the absence of moonlight, usually when the Moon's phase is between waning crescent and waxing first quarter.

Observers preparing for an evening of observing should bring along a few things: a sleeping bag or blankets for warmth, a recliner or lawn chair, and a hot beverage to help cut the chill. Binoculars are not necessary but they help. Wide-field ones are the best.

In group observing for meteors, each person has his or her own section of the sky to patrol. Wide-field binoculars can help an observer confine his or her attention to their own piece of sky.

Meteor trails make interesting photographs. Also, amateurs with a short-wave radio receiver can "listen" to meteors. This is done by tuning the receiver to a very weak distant station, preferably above 15 megacycles. The volume is kept very low. When a meteor in the upper atmosphere ionizes a patch of air, creating momentary "reflector" for signals, the volume of the station's signal rises sharply. Doppler changes in pitch may occur. On a good morning, several hundred meteors may be heard.

Meteor Activities You Can Do

  • Observe showers, alone or with groups.
  • Count the number of meteors seen in an hour. If observing a shower, count the number per minute.
  • On a star chart, plot the beginning and ending points of meteor trails.
  • If a meteor falls in your vicinity, try to find it. Watch your local newspaper for a report. Find persons who saw the meteor fall and attempt to trace it. Cooperate with a nearby observatory or museum, if any.

The above material is taken from the document, Meteoroids, Meteors, Meteorites and Tektites by James M. Thomas, last revised September 2, 2004.