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North American Meteor Network
The
eta Aquarid (ETA) meteor shower reaches a maximum on May
5th this year, at about 23 hours Universal Time (UT). This
is a particularly interesting shower as it is debris from
the famous Halley's Comet.
These
are fast meteors, travelling at about 66 km/sec, and will
seem to come from an area in the sky located at 338 degrees
ie. RA 22h 31.8m, Dec -01, which is very near the star eta
Aquarius on a star atlas. This is known as the radiant for
the shower. Check out the maps of the sky on the NAMN website
at http://web.infoave.net/~meteorobs/charts.html.
Aquarius
is on Map #3, and can be printed off by setting your printer
to landscape mode. Also check out the map of the eta Aquarid
radiant itself, on the International Meteor Organization
(IMO) website at the following address: http://www.imo.net/calendar/cal00.html#eta-Aquarids.
The radiant moves a little bit from night to night.
The
Zenithal Hourly Rate (ZHR) for this meteor shower is about
60 meteors per hour with the unaided eye. This is the number
of meteors, on average, that an observer would see from
a dark country sky if the radiant was directly overhead.
Your latitude and your time of night will affect your meteor
rates, as they affect how high the radiant is in your sky.
Unfortunately, we also have a bright moon for this year's
eta Aquarids, so the faintest meteors will not be seen.
Eta Aquarid meteors can be seen in lesser numbers until
about May 28th.
However,
it is still a treat to see this comet debris! Try to block
the moon from your field of view. This will help you see
more meteors. The nights around the date of maximum are
also worth observing, besides just the main night, as there
may be some other small peaks of meteor activity, perhaps
even until about May 10th. You can help us out by trying
to get data for some of these other nights.
Each
one of these meteors is a streak of light produced when
a small particle of debris from Halley's Comet strikes our
Earth's upper atmosphere and burns up due to friction. These
particles have been shed by the parent comet many years
ago. In fact, each time the comet passes through our solar
system, a new path of debris is created. The path of debris
that we encounter in one year might not be the same filament
of debris that we encountered in a previous year. This is
one reason why meteor shower rates can vary from year to
year.
For
more information on what to record when you watch meteors,
check out our NAMN Observing Guide at: http://web.infoave.net/~meteorobs/guide.html.
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