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This page was last modified on August 13, 1999 by Casper ter Kuile and Hans Betlem |
Fireball 29-05-1994 / 09:32 UT
Daylight fireball over the Northsea
Dear meteorfriends! This is the FIFTH and LAST newsbulletin of wednesday june 8, 00:00 UT on the bright Northsea fireball. This newsbulletin has been compiled by members of the Dutch Meteor Society including Hans Betlem, Jacob Kuiper, Marc de Lignie, Robert Haas, Marco Langbroek, Alex Scholten and Klaas Jobse. After we performed azimuth- and elevation-measurements at a number of observers we may come to a conclusion regarding the Northsea fireball of may 29. Date : Sunday, may 29, 1994 Time : 09:32 UT +- 1 minute Magnitude : Much brighter than the full moon, but less than the sun. According to many observers: on a scale from moon to sun, the brightness is more comparable to the sun. Most probable: -20 +- 3. Most observers report: intens flashlight, dazzling, like a welding flame. Duration : The brightest part of the fireball (the flash) lasted for about 2 +- 1 seconds. Because of the daylight the first part of the fireball has not been noticed by most observers. Observers : Observers are located along the whole Dutch coastal area which was mostly cloudless at that moment. Many observations have been recorded from the south-east coast of the British isles. Also observations from Belgium are reported. Direction : As seen from the province of Zeeland most observers report a north to north-west direction. Observers at more northern locations along the Dutch coast (Den Helder) report a western direction. The fireball has been observed by aircraft crew flying over the Netherlands. They too report a N-W direction. As indicated by Neil Bone from the BAA most British observers report the fireball east of Suffolk. This is in perfect agreement with Dutch observations. Elevation : Beginpoint about 10-20 degrees as seen from the Dutch coastal areas. Endpoint about 5 to 10 degrees. Height : The height of the fireball at the start of the brightest part is about 30 kilometres. The height of the endpoint is about 15 kilometres. Location : Combining the measurements of direction and elevation and the entrance angle should yield the trajectory of the fireball in the earth atmosphere. We now may conclude the fireball appeared about 100 to 150 kilometres west of Egmond aan zee. This little town at the Dutch coast is located about 40 kilometres south of Den Helder. Presumable the trajectory is directed from about NNE to SSW. Length : Dutch observers note the length of the brightest part of the fireball is short: about 5 to 10 degrees. Entrance : The entrance angle is supposed to be 45 to 60 degrees. Velocity : From duration and length of the trajectory we may calculate the velocity: about 10 kilometres/second. Colours : Many colours have been reported. Most reported colours so far are: light yellow to red. But also green and blue is reported. Neil Bone reports a typically yellow-orange object, with distinct head followed by a short "tail". Some observers report a dust-trail. Trail : As the meteor appeared in daylight hours this is hard to tell. Pers. train : Many independent observers report a smoke/dust-trail lasting from some minutes to half an hour! Reported colours are: white, grey and blueish. Images from METEOSAT and NOAA weather satellites do not show the above mentioned smoke/dust-trail. Photo's : We regret we have no photo's available of the smoke/dust-trail but are still working on it. Fragmentation: Most Dutch observers do NOT report any fragmentation. But an UA aircraft crew reports a rain of flashes. Also from BBC-text one may deduce observers have seen fragmentation. This should be clarified. Shockwaves : No shockwaves are recorded by the Dutch Meteorological Office while the fireball appeared above the tropopause. Sound : Not reported by Dutch observers. Satellite : No satellite re-entry is expected due to the big entrance angle and no entry was expected. Impact : Combining all information now available we now presume a meteorite fall (splash...) is possible! Please note the low velocity and no fragmentation make this assumption acceptable. Orbit : Orbital calculations lead us to the conclusion the Northsea fireball is a member of the asteroid belt between Mars and Jupiter. The computed low inclination too points to this conclusion. Radar : Has to be determined yet from Dutch air command. Remark : Note that direction and elevation have been measured from visual observations made by non-professionals. Data presented in this report should therefore treated with care! This is why we include relatively large margins to the figures given above. This newsbulletin will be send to all known observers of the IMO in western Europe, to the FIDAC Administration and to SEAN (Brian Marsden). A report on this extremely bright fireball will be published in WGN, the journal of the IMO. The Dutch Meteor Society would be much pleased to learn more about this extraordinary fireball. Especially more detailed observations from the British isles are much welcomed. If very important observations will come in which might change our conclusions we will let you know. We would like to thank all observers for their valuable observational reports without we would not be able to derive the characteristics of this very exceptional fireball. Please send all reports to the address below: Many best wishes, Casper.
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This page was last modified on August 13, 1999 by Casper ter Kuile and Hans Betlem |