ALPO Meteors Section

The peak of the 1998 Leonid meteor shower (rich in bright fireballs), shown in a four-hour time exposure through a fisheye lens, and taken by Juraj Toth of Modra Observatory. This photograph demonstrates how the meteors in a particular shower appear to emanate from a certain point in the sky called the radiant. On a given night, this radiant point will remain relatively stationary with respect to the background star constellations; but will rise, traverse the sky, and set in the same manner as the sun and moon.

• Viewing Meteor Activity
• Viewing Activity from the 2010 Lyrid Meteor Shower
• 2009 Meteor Shower Calendar
• Explanation of the 2009 Meteor Shower Calendar
• New Meteors Book Available
• Additional On-Line Resources

Viewing Meteor Activity

Since meteors are a transient phenomena one cannot go outside at night and expect to see meteor activity. This is especially true during the evening hours when the Earth is moving in the opposite direction from the sky seen above during those hours. At this time of night meteoroids (meteors in space) must catch up to the Earth in order to enter the Earth's atmosphere. Therefore meteor rates are lowest near 1800 (6:00pm) local time. Conditions for viewing meteor activity improves as the night progresses. At midnight a great majority of the meteors seen strike the Earth from a perpendicular angle instead of from behind. These conditions offer better rates than witnessed early in the evening but the general activity is still low when compared to the morning hours. During the dark morning hours the Earth is rotating toward the direction it moves in space, known as the apex. During this time the Earth slams head-on into meteoroids and many more will be seen. This is much like a vehicle driving through the rain. More raindrops will strike the front windshield compared to the rear window. The peak meteor activity occurs near 0600.

In addition to the diurnal cycle there are also annual variations in the meteor activity. As seen from the mid-northern hemisphere the second half of the year is much more active than the first six months. The reason for this are several. First of all the sporadic (random) meteor activity is stronger during this period. Also most of the major annual showers active during the second half of the year have radiants located north of the celestial equator, favoring northern obserevers. The cycle seen from the mid-southern hemisphere is opposite with the better activity occurring during the first half of the year. Observers at the equator enjoy fair, but not exceptional activity all year long.

During certain times of the year the major meteor showers are active and increase the nightly activity severalfold. This is especially true if the moon is near its new phase and not brightening the nighttime sky. The list of these showers is provided below (see the class I showers).

This is also the best time to see fireballs, which are exceptionally bright meteors that can light the nighttime scene. These meteors can range from the light of the brightest planet Venus (magnitude -5) to that beyond the light produced by the full moon (magnitude >-13).

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This double bursting fireball was photographed at 23:45 Universal Time on August 6, 2007 by Maurizio Eltri from central Venice, Italy. He estimated this sporadic (random) fireball to be of maximum magnitude -8, which is nearly as bright as the half moon. Picture courtesy of Maurizio Eltri, (Unione Astrofili Italiani Sezione Meteore).

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To keep current on the upcoming meteor activity the Meteors Section invites you to subscribe to their quarterly newsletter, available for the price of postage (currently 44 cents per issue). To subscribe contact our section coordinator Robert Lunsford.

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Viewing Activity from the 2010 Lyrid Meteor Shower

This chart represents plotted Lyrid meteors (arrows) seen from 40 degrees north latitude while facing north near 0500 local daylight time on April 22nd. This chart was created using SkyChart III Version 3.5.1 from Carina Software.

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The Lyrids are active from April 16 through the 25th. Peak rates for this shower occur on the 22nd when rates can approach fifteen Lyrids per hour. Five Lyrids per hour can appear on the 21st and the 23rd. Away from these three nights, the Lyrids are weak, only producing 1-2 each hour.

At the time of maximum activity the Lyrid radiant is actually located in eastern Hercules, seven degrees southwest of the brilliant star Vega (Alpha Lyrae). This area of the sky lies below the horizon during the early evening hours. Therefore no Lyrid activity can be seen until the late evening hours. The radiant attains a decent elevation between midnight and 0100, depending on your latitude. It is best situated high in a dark sky just before the start of morning twilight. Your best rates will occur during the last dark hour before dawn.

On the night of maximum activity the moon will be just past its first quarter phase and will set between 0100 and 0200 local daylight time for most locations. Observers in the southern hemisphere will see very little Lyrid activity as the radiant will be located low in the northern sky. All Lyrid meteors will trace back to the radiant area in eastern Hercules. There will be other showers and random activity visible during this period so not all meteors will be members of the Lyrid shower. Lyrid meteors will appear to travel swiftly through the sky unless they are seen near the radiant or near the horizon. Lyrids seen there will move more slowly as they are moving towards you (if seen near the radiant) or away from you (if seen near the horizon). On occasion the Lyrids produce fireballs, meteors that exceed the brightness of the planet Venus (magnitude -4).

The Lyrids are particles from Comet Thatcher (C/1861 G1). This comet has an orbital period of 415 years and the last time it was a perihelion was back in 1861. This shower has produced several notable outbursts. These occurred in the years 1803, 1849, 1850, 1884, 1922, 1945, and 1982. The 1803 event seems to the strongest as rates exceeded 500 Lyrids per hour at maximum. The 1982 event was seen from eastern North America where rates were estimated near 100 per hour at maximum. I witnessed the final portions of this outburst as I drove out to dark sky site. At that time, Lyrid meteors were seen shooting upward from the northeastern horizon. Once I arrived at my site the outburst was over and very little activity was seen the remainder of the night. The next possible outburst for this shower is predicted to occur in 2040 and 2041.

If you would like to contribute more to our knowledge of the Lyrids then I invite you to get serious about meteor observing and to make an hourly count of the activity you witness. Other more detailed projects include the estimating the magnitude, velocity, and color of each meteor. Others also note whether there was a persistent train after the meteor has vanished. Meteor watching can be both fun and scientifically useful endeavor. To be scientifically useful you must share your data with an active meteor organization such as ALPO. We accept data from observers with all levels of experience. Our data is published in our quarterly newsletter. The easiest way to share your data is to email your results to our section coordinator Robert Lunsford. We look forward to hearing from you!

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New Meteors Book by ALPO Meteors Recorder Robert Lunsford

The focus of this book is to introduce the novice to the art of meteor observing. It explains in straightforward language how best to view meteor activity under a variety of conditions, regardless of the observer’s location. The observing conditions for each meteor shower are vastly different from each of the Earth's regions and this book would be valuable to any potential observer from Australia to Alaska. The calendar chapters list activity as it occurs throughout the year. The list is limited to showers that the amateur observer can actually see (some sources list radiants that are impossible to observe without photographic or video methods). Not only are the annual showers discussed, but the random sporadic meteor activity is also included for each region. This is important, as there are many more nights throughout the year when the sporadic background will provide more activity than that provided by the annual showers!...more on http://springer.com/978-0-387-09460-1

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Additional On-Line Resources (Provided by the American Meteor Society)

• Frequently Asked Questions about Meteors and Meteor Showers, a FAQ sheet containing more in-depth information on this topic.

• Robert Lunsford's Weekly Meteor Outlook, a weekly newsletter describing the meteor shower activity for a given week.

• Fireball Reporting Form, Report exceptionally bright fireballs.

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Comments and Questions may be directed to the Meteors Section Coordinator: Robert Lunsford

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Last Modified: January 5, 2010