> -------------------------------------
> I M O S h o w e r C i r c u l a r
> -------------------------------------
>
> PERSEIDS 2000
>
>Apart from the traditional maximum at a solar longitude of
>140.0 degrees, a pre-maximum peak has been observed for more
>than 10 years with variable strength. For the first time
>after the return of the parent comet 109P/Swift-Tuttle, the
>2000 Perseids do not show this early peak.
>
>The fresh Perseid peak was expected near 5h UT on August 12.
>The below Table gives a preliminary ZHR graph showing no
>significant maximum at this time. The traditional maximum of
>the Perseids was well pronounced in 2000. The peak time fell
>near a solar longitude of 140.0 degrees. The small number of
>observers covering the maximum allows us to give only a rough
>estimate of the amplitude of about ZHR0-120.
>
>We are very grateful to the following 49 observers who sent
>in their reports in time for this first activity overview:
>
>ANDLU Luka Andrisic (Croatia) LISIR Irena Lisovski (Israel)
>ARLRA Rainer Arlt (Germany) LUTHA Hartwig Luthen (Germany)
>ATAJU Jure Atanackov (Slovenia) MAKVE Veikko Makela (Finland)
>BACNJ N.J. Bachmayer (Germany) MARAN Antonio Martinez (Venezuela)
>BARAS Asaf Barveld (Israel) MARJO Jose dos Reis Martins
(Portugal)
>DEVMI Miha Devetak (Slovenia) MCBAL Alastair McBeath (UK)
>EINSH Shlomi Eini (Israel) MOLSI Sirko Molau (Germany)
>ENZFR Frank Enzlein (Germany) NAYAL Aliakbar Nayyeri (Iran)
>FESMO Mohsen Fesharaki (Iran) OSAKA Kazuhiro Osada (Japan)
>GLIGE George W. Gliba (USA) PALER Eric Palmer (USA)
>HALCA Cathy Hall (Canada) PARMO Mojahed Parsi (Iran)
>HASAM Amir Hassanzadeh (Iran) PERSU Suyin Perret Gentil
(Venezuela)
>HASTA Takema Hashimoto (Japan) PEYNA Najmeh Peyvandi (Iran)
>HAVRO Roberto Haver (Italy) PLSMA Martin Plsek (Czech
Republic)
>HEVZO Zoltan Hevesi (Hungary) RENJU Jurgen Rendtel (Germany)
>HODKE Ken Hodonsky (USA) SERMI Miguel A. Serra (Spain)
>HORKM Kamil Hornoch (Czech Rep.) SKOIV Skokic Ivica (Croatia)
>IVAMA Marko Ivanovic (Croatia) SWADA David Swann (USA)
>JERMA Maja Jeromel (Slovenia) TRIJO Josep Trigo-Rodriguez
(Spain)
>KACJA Javor Kac (Slovenia) WUSOL Oliver Wusk (Germany)
>KHOSA Saedeh Khoshabadi (Iran) YOUKI Kim Youmans (USA)
>LEHMA Lehky Martin (Czech Rep.) YRJIL Ilkka Yrjola (Finland)
>LEUMA Marko Leustek (Croatia) ZAGDA David Zagorc (Slovenia)
>LEVAN Anna Levina (Israel) ZNOVL Vladimir Znojil (Czech
Republic)
>LINMI Mike Linnolt (USA)
>
>Date Time (UT) Sollong nObs nIND nPER ZHR
>Aug 11 1840 139.378 11 8 263 40 +- 2
>Aug 11 2100 139.472 15 13 88 37 +- 4
>Aug 11 2200 139.512 19 15 192 57 +- 4
>Aug 11 2300 139.552 17 16 248 55 +- 4
>Aug 12 0000 139.592 22 18 387 55 +- 3
>Aug 12 0100 139.632 28 21 796 69 +- 2
>Aug 12 0200 139.672 24 20 709 75 +- 3
>Aug 12 0330 139.728 3 3 78 84 +-10
>Aug 12 0730 139.891 4 2 130 82 +- 7
>Aug 12 0850 139.945 8 6 125 82 +- 7
>Aug 12 0950 139.985 7 4 149 105 +- 9
>Aug 12 1100 140.031 5 2 103 130 +-13
>Aug 12 1500 140.191 6 2 200 62 +- 4
>Aug 12 2240 140.498 10 3 64 29 +- 4
>Aug 13 0220 140.644 6 4 55 28 +- 4
>Aug 13 0650 140.824 11 3 178 48 +- 4
>Aug 13 2210 141.438 4 2 20 18 +- 4
>
>Solar longitudes refer to equinox J2000.0. nObs is the number
>of individual observing periods, nIND is the number of individ-
>ual observers providing them, nPER is the number of Perseids
>seen. The radiant position was assumed at alphaE, delta=+58,
>the population index used was r=2.0. The expectation value of the
>ZHR,
> ZHR = (1 + sum nPER) / sum(Teff/C),
>was used for the averages here, where Teff is the effective
>observing time and C is the total correction composed of limiting
>magnitude, clouds, and zenith correction. Times are rounded to
>the nearest 10 minutes.
>
>
>Rainer Arlt, 2000 Aug 16
>--
>Rainer Arlt -- Astrophysikalisches Institut Potsdam -- www.aip.de
>Visual Commission - International Meteor Organization -- www.imo.net
>rarlt@aip.de -- phone: +49-331-7499-533 -- fax: +49-331-7499-526
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