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Re: (meteorobs) Fwd: (Unusual?) Leonids from Central PA USA, 17/18 Nov 2000

Joe Rossi wrote:
>
> From: Joe Rossi <rossi3@netzerodot net>
> To: <meteorobs@jovian.com>
> Date: Fri, 24 Nov 2000 11:40:55 -0500
>
> Members of ASH and I were viewing the Leonids from Weiser State Forest =
> early Sat. morning. We where there from 2200 to 0430. I personally =
> witnessed 2 such meteors that night. These types are different in that =
> they appear to drop nearly vertically from the sky instead of cruise =
> across the top of it. These were also very bright and disintegrating =
> fragments were visible. This vertical trajectory implies the best =
> possibility of a near obervers impact. One such vertical meteor seemed =
> to drop right in towards the direction of Lancaster from our position. =
> The time was about correct also.
>
> Regards,
> Joe
>

Hi Joe:
    I read your message on meteorobs regarding the vertical or near vertical
fall of the two meteors you witnessed.  From a single location, it is
impossible to predict where a meteorite will fall.  One cannot even be
certain of the direction of flight.  To predict a fall area with any
certainty you must have observations from at least two different locations.
The more locations the better as then observational errors more or less
average out.  We often get reports that state that the meteorite dropped
just behind that barn or hill.  What one must realize, is the visible track
of the meteor is still high in the atmosphere.  Low points, or end points
can be as low as 50,000 feet or so but even from that height the fall area
can be quite large.  Also as stated above, it is impossible to predict a
fall area from a single observation site.  That is why filling out a
fireball report is important so your observation can be compared to other
sites.  What is required, is the azmith direction, corrected for magnetic
deviation for your location, and elevation above the horizon, measured with
a clinometer or protractor, for the point you first saw the meteor.  Then
the same measurements again for the last point you saw the meteor.  Your
location is also important.  This can be obtained from topographical maps or
by using a GPS.  Other things to note is the "time", include the time zone
or time used, and any record of delayed sound such as a sonic boom, and
similtanious sound if there was any.  The latter is still somewhat
contraversal but is of interest should it occur.
    I hope this clears up the points on what should be reported if one
observes a bright fireball.  Reports can be sent to:

Canada only:  http://dsaing.uqac.uquebecdot ca/~mhiggins/MIAC/fireball.htm
U.S.A. (AMS): http://amsmeteirs.org/
            NAMN - North American Meteor Network
global (IMO): http://www.imodot net/fireball/report.html

Ed Majden - MIAC Associate - AMS Affiliate


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