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(meteorobs) Fireball Reporting Part 1
FIREBALL REPORTING
by: George Zay
Revised: January 1997
Fireballs is the term given to brilliant meteors. Depending
on who conducts the survey, a fireball can be of magnitude -3,
-4, or -5 or greater. The International Meteor Organization
(IMO), recognize fireballs with a beginning magnitude of at
least -3. Usually though, when the general public takes note
of a bright object streaking across the sky, the magnitude is
probably far greater. We are talking about objects that creates
a lot of excitement amongst the general public. So much so,
that a lot of well meaning people often report a plane crash
complete with hearing an exlosion. Other's recognize it as an
exceptional meteoric event and thru their excitement, felt
compelled to just "reach out and tell someone". These objects
are most likely greater than -10. The one's that cause real
excitement are fireballs that produce sonic booms. Fireballs
that do this are known as bolides.
Beyond the local area, these exceptional events usually don't
get reported to those who records data about them. Often when
they are conducted, useful information is rather scarce. Peo-
ple just aren't conscious as to what constitutes useful infor-
mation. The minimum amount of information that has some value
for data gathering purposes is a report that simply states the
sighting of a very bright object. At least that adds to a sta-
tistic that may show the fireball activity that can be expected
for such and such date. That's bare minimum! But there's other
information that can make this report more valuable. Irregard-
less who you send your fireball reports to, ultimately they end
up at IMO's FIDAC (Fireball Data Center) in Germany under the
direction of Andre Knofel. In essence, FIDAC has become the ma-
jor collection point for fireball data. Information about fire-
balls worldwide is entered into it's database. Bi-monthly fire-
ball information is published in IMO's "FIDAC NEWS" printed in
English.
FIDAC has made up a Fireball Report Form. It's essentially a
check list for information that has value. Meteor observers
are quite familiar with this form. But there just aren't enough
of us at any given time to be earth's sky falling watch dogs.
This is where the casual observers and other astronomy inter-
ested people can help. Besides gathering data about what they
personally witnessed, they can also report what they read or
heard in the local news media.
FIREBALL INFO TO REPORT
Below is an itemized list of what is needed to report a fire-
ball.
DATE: year, month and day. Pay attention to correct day if
the event occurred after midnight. Give Double Date if you can.
ie. Nov 19/20 is the evening of Nov 19/and the morning of Nov 20.
LONGITUDE, LATITUDE, AND ELEVATION: Give these for the location
where you observed the fireballl. Give in Degrees, minutes and
seconds if able.
TIME: Use Universal Time. If you don't know how to convert to
Universal Time, use local time instead. Show your Time Zone. It
is best to get the meteor's appearance down to the second. But do
the best you can in this respect.
APPARENT PATH: Use one or more methods. Equatorial and Azimuth
are both astronomical co-ordinates. These are preferred. Des-
criptive is simply describing direction by points of a compass.
Ex. Meteor Traveled from Northwest to Southeast.
APPARENT MAGNITUDE: Any meteor that appears to be brighter than
-3 magnitude is considered to be a fireball. It may be helpful
when determining fireball magnitudes by recalling the following
magnitudes to compare: Sirius -1.4, Jupiter -2, Venus -4, Crescent
moon -6, Quarter moon -8, Full moon -12, and sun -27. If unfamil-
iar with magnitudes, perhaps it best to state if meteor appeared
to be brighter than Venus, Quarter moon, or Full moon. You might
also want to indicate whether or not that light was seen on the
ground.
PERSISTENT TRAIN: This is the ionized trail left by a meteor after
it's passage. Mention how long it lasted in approximate seconds.
SPEED: List the approximate speed by choosing the appropriate
number from the 1-5 scale. This might take a little practice. If
the meteor is visible for at least 30 seconds and traveled across
120 degrees of sky...assign a 1. Kind of Slow will last for about
15 to 30 seconds for the same distance...give these a 2. Medium
(3) 5 to 15 seconds across 120 degrees of sky. Somewhat fast, but
still can see the meteor's head is is a 4. If just a streak is
noted, it is a 5.
DURATION: This indicates an estimated length of time the meteor
was visible in seconds or fractions of.
COLOR: List the predominant colors(Blue, Green, Yellow, Red and
white).
FRAGMENTATION: Approximately how many observed fragments and
their magnitudes.
SOUNDS: List any apparent meteor caused sounds. If any occurs,
it will most likely be a very loud sonic boom or just a rumbling
noise. The most needed information here besides reporting a sonic
boom, is an approximate time of occurrence and how many seconds
elapsed from the time you first saw the fireball till the time
you heard the noise. Meteor sounds often occur up to several min-
utes after the meteor passes. Also, report any other towns that
reported sonic booms or rumblings.
OBSERVERS: In case a follow up is necessary, your name and
address is needed. If you know of multiple observers, list them.
If you know somebody with exceptional data such as video, photo-
graphs or meteorite recovery, give name and address also.
ADDITIONAL REMARKS: Show sketches, drawings or any additional
pertinent information you feel are important.
After completing the Fireball Report to the fullest of one's
ability, send data immediately to FIDAC directly or to George
Zay. The appropriate addresses are below. Please be aware that
just because a lot of data may not be obtained, a fireball re-
port is still important. Also, a little bit of accurate infor-
mation is better than a lot of questionable data.
Fireball Data Center
c/o Andre Knofel
Saarbrucker Strabe 8
W-40476 Dusseldorf
Germany
email: aknoefel@ddorf.rhein-ruhrdot de
or to:
George Zay
3946 Paula st.
La Mesa, Calif.
91941
email: GeoZay@aol.com
(continued in part 2)