Electronic Telegram No. 788 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://cfa-www.harvard.edu/iau/cbat.html 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. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2006 CBAT 2006 December 28 (CBET 788) Daniel W. E. Green