The meteoroid influx into the Earth's space environment
is not constant. It varies throughout the
day, with the seasons, and from year to
year. Unfortunately, there are now almost no
continuous monitors for this aspect of space weather.
Useful indices or measures of meteor activity vary
according to the customer affected. Radio users of
meteor ionisation tend to perceive a smoother variation
of activity than do visual observes. This is
because radio signals make use of a meteor
population that is created by considerably smaller meteoroids
than those that are optically visible. Meteor shower
phenomenon is less apparent in these fainter meteors.
Variations of activity for meteor radio systems
are most usefully indicated by two graphs which show
the typical diurnal and annual
variations.
For visual meteor observers, the following list shows
a few major showers that can be seen
at the specified times in the Australasian region.
The best time to observe meteors is usually
the hour before dawn (3 to 4am local
time). However, a few meteor showers are visible
only in the evening hours.
Shower meteors appear to radiate from the constellation
whose name they bear.
Shower Peak Velocity Visual
Name Activity (km/sec) rate/hour
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Lyrids Apr 21 48 5
Eta Aquarids May 04 64 20
Delta Aquarids Jul 29 41 30
Orionids Oct 21 66 20+
Taurids Nov 03 30 5+
Leonids Nov 17 72 5+
Geminids Dec 13 35 50
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See also Meteors: A Component of Space Weather
Educational