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METEORS
SHOWERS
I
hope one day you will observe a bright meteor. Nothing is most easy as you can
do it naked eye, without telescope ! Take with you a lounge chair, optionally
a sleeping bag, hot coffee or thee, gloves and your parka. Voilą, it
seems that you are organized to capture all meteors firing over your head.
Not really...
The
meteor hunter who hardly wants participating in an international
observer network cannot simply go out and watch the Perseids in August
and go sleep a few hours later. Your task consists to go out every time
you can to watch as many meteors as possible, including showers
known to perform poorly (small ZHR). You also need a tape recorder and
have to follow a strict procedure in order your observations be
comparable to other observers's reports and vice versa.
Once
ready, your local section manager will assign you a quadrant or chunks
to survey. In that area you should note for each meteor its time of
apparition, location, direction, duration, characteristics, etc. This is
a dedicated task asking patience and attention to details.
Otherwise your observation is useless except if you consider its poetry
and artistic value.
The
simple report of their accurate trajectories and parameters are enough
to conduct a scientific program. The rest is affair of geometrical
transformations from one coordinate system in another.
Another
way to survey the meteors activity is participating in an all-sky
photographical survey. Your equipment is either one or more cameras using fast
film and wide-angle objectives on which are fixed a rotative shutter or
a simple videocam filming a convex mirror from above. In this latter
case, the rotative shutter is useless. This way you could estimate both the speed of meteors and their
evolution along their trajectories, including their color and occasional
smokes when disappearing as you can see on the animation at left.
Major
associations will assign you a specific quadrant of the sky to ensure a
continuous watch and systematic coverage of the sky around the world. In
some occasions you can be the only person in the world scrutating the sky!
At
last you have the opportunity to study the meteors spectrum and
searching for the "green auroral" line, an emission line
from the O I at 5577 Å that appeasr somewhere around 100 km high and rarely recorded.
Agreat part of the actual research
on meteors is defining the origin of theses particles. Roughly told we can split them in two
main groups :
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The one of cometary origin, most of them having a large orbital
inclination;
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The one of asteroidian origin with a small orbital inclination.
Many bright bolids own to this last group.
Since
1982, IAU has organized at Lund Observatory in Sweden an international
centre in charge to observe meteors and analyze reports. These
professionals accept also observations from the amateurs community.
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Major
meteors showers
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Shower
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Date
of maximum
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Number
of meteors (ZHR)
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Quadrantides
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4
January
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85
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Aquarides
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5
May
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35
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Perseides
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12
August
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75
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Orionides
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22
October
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25
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Leonides
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16
November
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25
- 1000
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Geminides
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13
December
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75
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At
last, learn how to listen meteors and
use their ionization trace to contact radio amateurs by shortwaves.
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to Reports & Reviews
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