Appeal for assistance on Fireballs

Wayne T Hally (meteors@eclipse.net)
Wed, 7 Jul 1999 12:24:32 -0400

Greetings SeeSat'ers,
	I am writing today to appeal for you to provide invaluable help in 
collecting data on fireball meteors. The SeeSat audience has a unique set 
of skills which would make your observations much more valuable than the 
general public. These are
1. Your familiarity with the night sky
	Most people who see and report a fireball (a meteor as bright as Venus or 
brighter than ~ Mag -4) really don't have much of a clue about where they 
are in the sky, and the reports are therefore notoriously bad. On the other 
hand, we know RA and Dec, the constellations, and can give accurate Azimuth 
and elevation information. This skill is priceless. The average person 
severely underestimates elevation particularly.
2. Your experience in estimating magnitude
	Of course, if you see a -12 fireball, there aren't a heck of a lot of 
reference points available, ( Venus -4, Crescent moon -6, Quarter moon -8, 
Full moon -12, Sun -27) but still, at least you know what a -4 to say -9 (a 
"benefit" from Iridiums:->) object would look like, and any extrapolation 
done above that for brighter objects would likely be better than the 
average man off the street.
3. An accurate timepiece.
	This is also very important. A typical fireball report has times scattered 
over 5 minutes to an hour, since most folks are not carrying around a 
timepiece calibrated to UT, and are not obsessed with keeping it that way. 
We are :->
4. Finally, you're out there!
	Most fireballs occur during the evening hours (due to various reasons that 
I won't go into here, but will be happy to answer privately) just at the 
time when satellites are in the sun, with us in the shade. So we are 
looking at the sky.

	I do observe satellites during my meteor watches. I can't do detailed 
observations, since the meteor observing is my primary goal, and I can't 
take my eyes of the sky, lest I miss one. However, on my meteor tape, I do 
record all satellites seen with magnitude, motion, and timing 
information...and I attempt to time flash periods as well. And I understand 
that you are out there doing satellite observing. However, fireball meteors 
are so rare, and there is so little quality information recorded, that I 
would ask that if you see a meteor brighter than Venus, you record the 
information as accurately as possible. In general, the info is Az and Alt 
of start and end, duration of the meteor, magnitude, time, whether any 
fragmentation occurs, whether there is a visible train or smoke trail 
afterward, and finally any sounds heard. They consist of so called 
electrophonic sounds, which happen at the same time as the meteor (rare, 
and with no agreed upon scientific explanation) and sonic booms, which will 
occur from one to many minutes later (since fireballs tend to terminate 
from 10 miles and up, and may be seen as far away as 500 miles (800 km) at 
an elevation of 5 degrees, it can take that long for the sound to arrive at 
5 seconds per mile). These generally have only been reported for fireballs 
-10 or brighter, but more data is needed.
	Here is a URL for a Fireball report form that you can print out and keep 
in your satellite observing kit.
http://web.infoave.net/~meteorobs/fireball_form.html
	If you'd like more information on fireballs in general:
http://web.infoave.net/~meteorobs/guide.html  (The North American Meteor 
Network)
http://207.8.157.81/    (the American Meteor Society)
http://www.imo.net/    (The International Meteor Organization)
	Or feel free to write to me at meteors@eclipse.net if you have any 
questions, need any assistance filling a form out, or need some forms or 
more information.

Thanx for your assistance and cooperation.

Meteor Wayne
NJAA, NAMN,AMS,IMO