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(meteorobs) revised trajectory DMS 310799 fireball



Dear all,

We have revised the trajectory results for the impressive fragmenting
fireball of 31 July 1999 over the Netherlands, reported in an earlier mail.
While starting point and general direction remain similar to our earlier
results, the end point has been revised considerably. We now believe the
fireball travelled a much longer trajectory. Below is an excerpt from our
revised website bulletin: a map with the trajectory can be found on our
website (see below):

"A revised trajectory based on observers who give sky coordinates of start
and end point indicates a long trajectory of 180 km length. The object came
approximately from azimuth 325 degrees (N-NW, travelling towards S-SE)
appearing first over the Dutch part of the North Sea some 50 km outside the
Dutch coast (about 52d 35' N, 3d 50' E), roughly ~75 km NW from Amsterdam.
There is some leeway in the true starting point since many observers
presumably missed the early part of the appearation. The object entered the
coastline between Leiden and The Hague just
halfway on its trajectory, and ended on the Dutch-Belgian border, in the
southeastern
part of Dutch Brabant (about 51d 20' N, 5d 25' E) approximately 15 km south
of Eindhoven.
 Again, there is some leeway in this position because some observers saw
the fireball disappear behind trees etc. and therefore missed the true end
point. We have too little accuracy in the results for a reliable end-height
determination, but it is suggested to be roughly in the order of 60-70 km
altitude: this was a grazing fireball.
 The velocity very roughly can be determined at between 15-35 km/s. This is
too large for a satellite decay (typically about 7.65 km/s), moreover no
satellite decay was expected for this time and location according to Alan
Pickup (UK)."

Marco Langbroek
Dutch Meteor Society (DMS)

       
Casper ter Kuile, Dutch Meteor Society (DMS)
Akker 145, NL-3732 XD, De Bilt, The Netherlands
Tel. +(31)-30-2203170, Fax. +(31)-30-2202695
GSM-BEN: +(31)-6-24242445, GSM-KPN: +(31)-6-53270844
E-mail_1: pegasoft@accu.uudot nl
E-mail_2: dms-web@wxsdot nl
DMS website: http://home.wxsdot nl/~dms-web/index.html
 
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