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Re: (meteorobs) Going by logic...
Hi Wayne,
> Lew, as I understand it (which may not necessarily be right), they would be
> brighter due to the fact that they penetrate to a lower level in the
> atmosphere. Note on the height chart of the IMO handbook (Chapter 1 I
> think), that bolide type objects are shown at 10-20 km final elevation.
btw, the figure you mention is acutally not the very best one, in
particular the given end heights for fireballs. Usually all bright
bolides finish at altitudes well above 50 km. Everything that makes it
down to 10 or 20 km can potentially fall on your head. ;-)
I guess what they meant was, that the luminous trail of fireballs end *at
last* at an altitude of 10 to 20 km. If the meteoroid is still there, it
will continue falling to the ground, but produce no visible emission
anymore. This is the reason, why it is so extremely difficult to get
accurate predictions for the impact areas of possible meteorite dropping
fireballs.
Up to an altitutde of ~15 km you can determine the position of the
penetrating body with an accuracy of a few tens of meters (taking
good photographs from the European Fireball Network, for example).
However, you can only guestimate what happens afterwards, and in the best
case (optimal geometry of the cameras, good knowledge of the wind
direction and speed in the different atmosphere layers) the predicted
impact area is about 1 square kilometer in size.
Sirko
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* Sirko Molau * __ *
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* http://www.snafudot de/~smo * *
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