Electronic Telegram No. 1188
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html


URSID METEORS 2007
     P. Jenniskens, SETI Institute, reports on elevated Ursid shower rates
between Dec. 22d18h and 23d01h UT, identified as dust ejected from comet
8P/Tuttle prior to 900 AD (cf. CBET 1159).  The outburst was detected in
radio forward-scatter meteor observations by E. Lyytinen (Helsinki, Finland)
during Dec. 22d18h-23d01h and by J. Brower (Vancouver, BC, Canada) during
Dec. 22d18h.5-22d22h.5.  I. Yrjola (Kuusankoski, Finland) reports that 25
Ursid meteors and 16 sporadic meteors were captured on video, with a peak at
around 21h15m, the Ursids being slightly brighter on average than other
meteors that night.
     The International Meteor Organization gathered visual observations from
19 observers, who measured a peak ZHR = 34 +/- 5 Ursids/hr (vs. predicted
40-70 meteors/hr) at solar longitude 270.53 +/- 0.03 deg during Dec.
22d21h12m +/- 42m, based on 116 Ursids (assuming a fixed population index
of chi = 2.5).  The predicted peak time was Dec. 22d20h-22d22h.2.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2007 CBAT
2007 December 31                 (CBET 1188)              Daniel W. E. Green