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(meteorobs) NAMN Call for Observations: Lyrids/Eta Aquarids
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NAMN Call for Observations: 1998 Lyrids and Eta Aquarids
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The first quarter of the year is somewhat barren of good meteor rates once
the Quadrantids end. This is a characteristic of the mostly minor meteor
streams active during this period. One possible exception, with a zenithal
hourly rate of 10 or more meteors, is the Lyrids.
This shower peaks on April 22 from a radiant that is near the star Vega.
Maximum rates are produced for only about an hour or two, but has been
known to be erratic. In 1996 for example, peak rates of 15-20 persisted for
8 hours or more.
The Lyrids are associated with Comet Thatcher 1861 I and have produced
several bursts of activity in the past. The most recent occurred over North
America in 1982. Rates at that time reached nearly 100 meteors per hour!
Useful watches can be carried out after 2230 hours local time when the
radiant has reached sufficient height above the horizon.
This year, we will be facing a waning crescent moon that rises a little
before dawn. But conditions will still be favorable for us and
opportunities to observe should not be missed since the predicted maximum
favors North American observers.
Specific information about the shower is listed below:
Lyrids (LYR)
Active: Apr 16-Apr 25
Maximum: Apr 22
Radiant: 271 +34 (18h 04m)
Velocity: 49 km/s
ZHR: 15
About two weeks later, another shower is visible that does produce good
rates for observers. The Eta Aquarids are the outbound particles of the
famous Halley's Comet. It has a long activity period and broad maximum
which can occur May 2 through May 10. Unfortunately for Northern Hemisphere
observers, its radiant favors the southern half of the globe. According to
the IMO, an observer may see nearly 40 meteors per hour at shower maximum
from tropical latitudes, decreasing to invisibility as you approach 50
degrees north latitude. Still, the shower is observable from some North
American locations. The Eta Aquarids are known to produce a high rate of
trains, normally exceeding all of the other major showers. One study has
train production as high as fifty percent!
Although the published ZHR for this shower is 60, that is the rate
associated with Southern Hemisphere locations. In North America there
have been various ZHR's published, but probably is at most 20 per hour and
is highly dependent on latitude. Keep in mind though, that they exhibit a
broad maximum, and rates are usually one-half the maximum rate for almost a
week centered on the main maximum.
Unfortunately, in 1998 this shower suffers from some moonlight as the moon
is about three days before full when they reach maximum. Below is the
specifics on this shower:
Eta Aquarids (ETA)
Active: Apr 19-May 28
Maximum: May 05
Radiant: 338 -01 (22h 32m)
Velocity: 66 km/s
ZHR: 60
Send all reports to:
Mark Davis
NAMN Coordinator
(email) MeteorObs@charlestondot net
Reporting forms and/or instructions on how to hold a meteor watch may also
be obtained from the above address.
- End -
Mark Davis, MeteorObs@charlestondot net
Mt. Pleasant, South Carolina, USA
Coordinator, North American Meteor Network
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NAMN home page:
http://medicine.wustldot edu/~kronkg/namn.html
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