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.

  
  ----------------------------------------------------  
  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 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).