FreeLists / az-observing / [AZ-Observing] Re: Meteoric observations need accurate reporting

["Kevin Bays" <bayskevin@xxxxxxxxxxxxxx>]

I also saw the bright meteor of June 9, with Sam Rua at Chiricahua National
Monument.  I also noted that it passed downward near Sagittarius.  I noted 2
or 3 bright flashes sufficiently bright to make me shut my eyes from the
discomfort.  I heard no sounds.  The color I noted was green.  The object
seemed to exhibit an elliptical-shaped head and a tail of maybe 5 degrees,
although I'm straining my memory re: the tail length.  Sam noted a color
change.  I think he mentioned an orange hue during part of the apparition.


----- Original Message -----
From: Bill Peters <afls@xxxxxxx>
To: <az-observing@xxxxxxxxxxxxx>
Sent: Monday, June 10, 2002 1:26 AM
Subject: [AZ-Observing] Meteoric observations need accurate reporting


>
> To anyone observing a extremely bright bolide (aka:  fireball).
>
> Most of the reportings of the June 9, 2002 fireball are too vague to be
able
> to triangulate the trajectory and locate a possible fall zone.
>
> There is great scientific value in the recovery of observed falls.  This
> best way for recovery of an observed fall that does not land at your feet
is
> for compilation of accurate reporting by multiple observers.  Even if the
> meteor has little chance of recovery or did not even survive entry it is
> still possible to compute a rudimentary orbit from accurately reported
> sightings and contribute to our understanding of bolides.  Scientists are
> theorizing that some Earth crossing meteorites travel in similar orbit
> families, but it has not yet been confirmed.  Of significant interest are
> the early June bolides and recovered meteorites. Early June holds the
> distinction of having both the most observed and recovered fireballs or
> anytime during the entire year.  Although there is no indication that this
> June 9 bollide landed it still is useful to learn from this event.
>
> Several pointers in reporting your observations of very bright meteors:
no
> observer can judge distance nor size of the event, only direction from an
> observers location.   Therefore give accurate location of observing site
and
> precise directional information of the travel path of the bolide.  There
are
> three primary observable events in the final flight of a bolide; its
entry,
> its oblation (explosive disintegration, the big flash sometimes multiple),
> and its point of dark body state where visibility ends.  It is important
to
> obtain info on where in the sky the meteor BEGAN, where is oblated
> (exploded), and where it ended (reached dark body state).  Most observers
> only view the final one or two events.  Essentially all meteorite falls
> reach dark body state before hitting the ground.
>
> Once a target area is located from distant observers it is very important
to
> find the closest observers to the fall site.  I am not surprised none of
the
> observers reported any sounds.  Likely they were too far away, or else
> distracted by what they had seen and their excitement in talking about it.
>
> Sounds are very important to listen for.  Bollide sounds can travel over
50
> miles, but the long distance and time delay are not realized by possible
> observer/listeners who are not paying attention or do not associate the
> sounds with the observed event.  Even the June 7, 1998 Stanfield, AZ Fall
> Meteorite people, who were just 8 miles away were surprised, by the sounds
> heard 40 seconds later - much later than what one would hear from
thunder -
> typically heard no more than 20-25 seconds after the strike.  There are
two
> distinct phenomena on bolide sounds: the simultaneous often radio-like
> static created in the same way, and the sonic booms of the meteor in
flight.
> The sonic booms are the key to judging distances.  The way to time and
> listen for them is begin counting immediately after you've seen the flash
> (explosion) until you can look at your watch to continue the count.
Cupping
> your ears with your hands will greatly enhance your listening ability.
You
> will need to keep listening for over 4 minutes.  Sound travels 1 mile per
5
> seconds.  Therefore if you do hear and time sounds you can easily compute
> distance.  I myself have heard a sonic boom from a military jet on a known
> path 45 miles away nearly four minutes after the event.
>
> Here are some basic questions to report after observing a bolide:
> 1    Where were you when you first saw the meteor?  (Give observing site,
> address,or unique identifying info)
> 2    At what point in the flight did you first notice it?
> 3    What did you see?
> 4    Where did it begin -if observed?
>     (Give degrees above the horizon, observed beginning point directional
> location, background star fields trees, houses, mountains or other
markers,
> precise direction of travel, repeat for next two questions.  Example: it
> began 30* above the horizon at the 1 o'clock position from North just to
the
> right of the tail star in the Big Dipper traveling ESE, it exploded at 70*
> above the horizon at the 10:30 position and I followed it until it reached
> the 8 oclock position 20 degrees above the horizon.  It the backgound I
> could see its endpoint was just to the right and above the right secondary
> peak of the Table Top Mountian.)
>
> 5    If is exploded, at what point(s) in the trajectory?
> 6    Where did it end?
> 7    Did you hear anything?  What did you hear?
> 8    Were you able to time how long after seeing the event before hearing
> it?
> 9    How bright was it?  Did you see your shadow?
> 10  What color was it?  Was the color consistant or did it change?
> 11  Could you observe a remnant trail after the event?  Where did the
trail
> end?
> 12  Who else do you know saw it?  Can they be contacted?
>
> Good reporting from multiple observers from different locations should
lead
> to plotting a rudimentary orbit and determining a scatter ellipse of a
> possible fall search.
>
> Bill Peters 480-813-4242
>
>
>
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