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(meteorobs) Fwd: [IMO-News] Underestimated fireball magnitudes

Forwarded with the author's permission.

Note, Pavol is not a current 'meteorobs' reader. So if you reply,
be sure to MANUALLY put 'bzucino@yahoo.com' in your "Cc:" line!

Clear skies,
Lew Gramer <owner-meteorobs@meteorobs.org>
Webmaster: http://www.meteorobs.org



-----Original Message-----
From: Pavol Habuda <bzucino@yahoo.com>
Sent: Sunday, April 11, 2004 6:17 AM
To: imo-news@yahoogroups.com
Subject: [IMO-News] Fwd: Underestimates values of fireball



Group of meteor observers were observing during last summer. We saw
fireball with magnitude -7 (-7,5 at max., data from Mr. Spurny,
Ondrejov Observatory, magnitude recalculated against distance), entry
velocity 40 km/s, angular velocity 20 deg/s, height above horizon 60
deg.

Magnitude data from observers follows: -4; -3; -5; -7; -2.5; -5 , other
observers saw illuminating of the ground. Magnitude compared with Mars
(-2.8). Average sky conditions (Lm 5.8-6.3).

And this give a rise to my question. Despite common accepted rule, which
says observers overestimating fireball`s magnitude, here we can see
inverse
effect -- almost all observers underestimate magnitude (me including).

Does anyone know or bear him to mind some plain explanation?



Clear skies
Pavol Habuda

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