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Re: stormlet (meteorobs) Views of Meteors


------- Forwarded Message from subscriber "Dustin"...

Date: Tue, 21 Dec 1999 21:18:48 -0800
From: Dustin <nospam@know-spamdot edu>
To: meteorobs@jovian.com
Subject: Re:stormlet (meteorobs) Views of Meteors 

Hi, I've just joined this E-mail group so this is a bit late and I don't
know if this was already posted:
Did NAMN or meteorobs  receive any reports of the group of five to six
Leonid fireballs seen within 2 seconds of each other in the same area of
the sky?   This fireball "stormlet" occured over northern Oregon /
southern Washington State USA at 10:43 UT  Nov 17/18 1999.  (2:45 AM local
time Nov 18) Observers at different sites estimated the first fireball at
about -10 (Tygh Ridge site) to a full moon -12 brightness (Celilo site).
(Thanks to Wes Stone for the accurate timing) This fireball was followed
immediately by 4 or 5 less bright ones all within a few degrees of each
other. The train of the brightest one lasted at least 40 minutes,
gradually turning into an odd shaped cloud.  Several members of the Rose
City Astronomers reported observing this in the northern sky from Tygh
Ridge in north central Oregon.   I observed this "stormlet" from Celilo
Oregon, which is 30 to 40 miles north of the Tygh Ridge site (sky's
limiting magnitude of approximately 6).  From my site the fireball also
appeared in the northern sky.  Since I was ~30 miles closer to the meteor
could this explain my higher estimated magnitude?   My surroundings lit up
as if the full moon had suddenly appeared in the sky.  (I must admit that
I am new to estimating magnitudes of objects.)   This dual observation
from seperate sites has spurred my interest in the procedure and math in
making accurate triangulations. (time for some web-searching)
The rest of the early morning  meteors were sporadic at about 30/hour and
dimmer at magnitudes of 2 and dimmer.  (The only other "fireball" that I
saw the entire night was hours earlier and at a magnitude of approximately
mag -2 to -3).
Wesley Stone from Rose City Astronomers lists a link to a similar
Leonid fireball "stormlet" video documented in 1997 over Hawaii at:

http://www2u.biglobe.ne.jp/~nms/kinosi_e.html

The video at this site looks very much like what we observed.  The video
does have more and brighter secondary fireballs than what we observed, but
the general appearance is very similar.   Too bad this years event wasn't
video captured as well.
I'm curious as to what might explain this very tight grouping of
fireballs.
Could they  be loosely held together in a small piece of cometary ice (a
chip off the old comet, so to speak) and this ice/rock "chip" breaks up
early in the entry into Earth's atmosphere releasing the multiple
fireballs ?
Any info/ideas anyone might have on any or all of my rambling questions
would be appreciated.

This experience makes me interested in participating in a formal count /
report for next years Leonids.   I had hoped to observe the 1999 Geminids
but Western Oregon was clouded over the entire time.

Dustin Brown
brodwcjj@integrityonline.com

Dave English wrote:

> Kevin did ask a good question about veiwing the same meteor
> from different locations.
>
>        Robert Lunsford saw that -9 Geminid from the Joshua Tree
> National Monument at 12:34 local time as it crossed Orion. I saw it
> much closer, it originated near my zenith and moved nearly directly
> west (275 degrees) over about 35 degrees distance. I gave it a very
> conservative -6 as I didn't want to overstate and cause unwarrented
> interest. I had wanted to post it as a -8 or more but with my lack of
> experiance with big meteors, I wanted to rely on more experianced
> observers like Robert for the correct magnitute. My first instinct
> seemed right about the magnitude.
>
>        Now about seeing the same meteor from different locations.
> Robert was at least 80 miles (129 km)NNE of my location in Oceanside
> and his location could easly have been 100-120 miles (160-193 km) away
> depending on what part of JTNM he was at. I saw the meteor start
> almost overhead and move directly toward the west and he saw it cross
> Orion somewhere and more westerly. With refined information we should
> be able to give a start and end altitude for this meteor if we want
> but the idea is the same meteor was seen at pretty good distances
> apart yet both were still high in the sky.
>
>                          Dave English
>                          Oceanside, Califoria

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