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 ZHR=110-120.

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Date   Time (UT)  Sollong nObs nIND  nPER  ZHR  +/-
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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
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Solar longitudes refer to equinox J2000.0. nObs is the number of individual observing periods, nIND is the number of individual observers providing them, nPER is the number of Perseids seen. The radiant position was assumed at alpha=45, 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.

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 Republic), 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 Republic), YRJIL Ilkka Yrjola (Finland), LEUMA Marko Leustek (Croatia), ZAGDA David Zagorc (Slovenia), LEVAN Anna Levina (Israel), ZNOVL Vladimir Znojil (Czech Republic) and LINMI Mike Linnolt (USA).