[IAUC] CBET 788: 20061228 : URSID METEORS 2006

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                                                  Electronic Telegram No. 788
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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CBAT en CFA.HARVARD.EDU (science)
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URSID METEORS 2006
     P. Jenniskens, SETI Institute, provides the following summary of
observations of Ursids, following his report on the predicted outburst of
Ursids (cf. CBET 773).  S. Nakano, Sumoto, Japan, reports that M. Ueda
(Habikino, Japan), using two low-light-level video cameras, recorded meteors
at a rate of 0.4 Ursids/hr (on average) prior to Dec. 22.791 UT, and with 3
and 4 Ursids/hr in the following two hours.  Visual observer A. McBeath
(U.K.) reports seeing the highest Ursid rates in the hour after Dec. 22.754
(12 Ursids) under non-ideal conditions.  M. Vandeputte (Belgium) observed
between Dec. 22.715 and 22.882, finding the highest rates to be 7 and 8
Ursids per hour (and 6 sporadic meteors/hr) in the two hours between Dec.
22.757 and 22.840.  E. Lyytinen (Helsinki, Finland), I. Yrjola (Kuusankoski,
Finland), and J. Moilanen (Vaala, Finland) detected meteors at a rate of 3.9
+/- 1.3 Ursids/hr at Dec. 22.667 and 4.5 +/- 1.5 Ursids/hr at 22.708 UT
using low-light-level cameras, with an average rate of only 1.3 Ursids/hr
between Dec. 22.875 and 23.250.  Radio forward-meteor-scatter observations
by I. Yrjola (Kuusankoski, Finland) and J. Brower (Kelowna, BC, Canada)
showed elevated rates between Dec. 22.50 and 23.00 UT.  From this,
Jenniskens calculates a peak ZHR of ZHR 15 +/- 5 Ursids/hr at Dec. 22.733
+/- 0.062 UT for the outburst component (the predicted activity for the
Ursid filament was ZHR around 39 Ursids/hr at Dec. 22.733; cf. CBET 773).
The Ursids were unexpectedly bright, increasing in number for every
magnitude only with chi = 1.9 +/- 0.3.


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                         (C) Copyright 2006 CBAT
2006 December 28                 (CBET 788)               Daniel W. E. Green