[Prev][Next][Index][Thread]

(meteorobs) Re: [Bolide_Chasers] Re: Bright Fireball!!


----- Original Message -----
From: "ldbenschop" Subject: [Bolide_Chasers] Re: Bright Fireball!!


> (2) Generally observers are familiar with the stars, constellations
> and will already have a pen and paper handy. The closer to the
> observation that notes are made the better. My notes were made about
> 1 minute following the observation of the meteor.
>
> Len Benschop
>

Len:
    What you say above is fine if experienced observers see and record the
fireball.  Unfortunately, this almost never happens!  You have to rely on
information extracted from the public who are often not familiar with the
stars or for that matter directions.  Also, what do you do about a daylight
fireball?  With this in mind, Dr. Jeremy Tatum, formally at the University
of Victoria and MIAC member trained a group of interviewers scattered across
the Province of B.C.  When a fireball occurs these volunteer interviewers
are alerted and spring into action.  They are equipped, (bought and funded
by themselves), a good compass, a clinometer or other elevation measuring
device, topographical maps for their area or a GPS.  The observer of the
fireball is taken to the location where he or she observed it and with out
influencing the observer, the person is asked to reconstruct what was seen
and the measurements are taken.  People often report the flight direction of
the fireball, it was going NE or SE etc.  From a single station, this
direction information can be inaccurate.  A fireball can be coming toward
you or going away from you and draw the same track on the sky.  It is better
to ask, was the fireball going from "left-to-right" or "right-to-left".
This is a quick way to determined if you have observers on both sides of the
track.  This is necessary if you want to do a triangulation and predict a
possible fall zone.  These interviews should be conducted as soon as
possible so the information is fresh in the minds of the witnesses.
Hopefully with in one week.  Observations from moving vehicles are discarded
as they prove to be inaccurate.  One should also try and find video
recordings of the fireball.  This is probably the only way to extract
"velocity" information which "IS" required if orbital data is to be
calculated.  Don't forget to check parking lot and other security type
cameras often found at business locations.  These security cameras may not
record the fireball directly but the may record the shadows created by a
very bright fireball.  Direction and elevation information can be extracted
from such photographs by studying the shadows.  Dr. Peter Brown at the
University of Western Ontario has used such information to plot fireball
paths.  Dr. Tatum has used information collected in the above fashion to
calculate fireball flight paths and orbits with several papers on this
subject to his credit.
    Bolide Chaser members interested in tracking fireball would do well to
organize such a volunteer network of trained interviewers.  Not all or many
fireballs are recorded by all-sky or photographic networks so one must use
observations collected from the public.
    Good luck!

Ed Majden - MIAC Associate
West coast Sandia Bolide Detection Station - Courtenay, B.C. CANADA
(un-official coordinator for this network)


The archive and Web site for our list is at http://www.meteorobs.org
To stop getting all email from the 'meteorobs' lists, use our Webform:
http://www.meteorobs.org/subscribe.html