Perseids 2001

The 2001 Perseids occurred under rather poor circumstances. Observers either had to put up with the adverse effects of a Last Quarter Moon or start early, in which case they had to deal with low radiant elevations. This resulted in a lot of scatter among individual data, from which it is hard to derive a clear pattern, especially in this early stage of data collection.

What we can conclude from the table below is that Perseid activity reached a very broad top level with a ZHR around 85 between roughly August 12, 9h UTC and the early UTC hours of August 13. There may have been one or more peaks in this long interval, they were surely not very outspoken. The individual ZHRs on which this table is based suggest such peaks around August 12, 14h UTC and August 12, 20h UTC, with ZHR of 130 and 105, respectively. Unfortunately, both possible peaks are covered by a few observers only, most of which are very perceptive, which is why these suspected peaks might be mere artefacts.

We remind the reader that the peak associated with the latest return of parent comet Swift-Tuttle could not be positively identified in the 2000 Perseid data. A very straightforward - but equally tentative - explanation of the current profile might be that whatever activity remains of the "first peak" smoothly flows over into the activity associated with the regular Perseid peak, thus creating a very wide and flat plateau of activity. A more thorough investigation of these and other data will be necessary to shed more light on this, obviously.

If you have not done so yet, please send your observing data as quickly as possible to the Visual Commission at visual@imo.net.

  
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  Date Time(UTC) SolarLong nObs nInd nPER ZHR +/-  
  -------------------------------------------------------  
  Jul 22 0000  119.25  7  3 14 5.8 1.5  
  Jul 27 0000  124.03  4  1 8 3.7 1.2  
  Jul 28 0000  124.98 20  7 49 5.7 0.8  
  Jul 29 0000  125.94  5  2 13 3.7 1.0  
  Jul 30 0000  126.90  7  2 21 5.4 1.2  
  Aug 07 2100  135.39  3  1 8 13.2 4.3  
  Aug 09 0000  136.47  5  1 12 12.6 3.5  
  Aug 11 0000  138.38  6  6 81 37.4 4.1  
  Aug 11 1430  138.96  6  3 79 66.9 7.4  
  Aug 11 2115  139.23 16 13 233 46.1 3.0  
  Aug 11 2230  139.28 15 12 273 45.1 2.7  
  Aug 11 2330  139.32 14 10 192 61.3 4.4  
  Aug 12 0050  139.38 15 10 223 69.4 4.6  
  Aug 12 0150  139.42 13  9 297 55.8 3.2  
  Aug 12 0415  139.51 10  5 175 54.5 4.1  
  Aug 12 0900  139.70 13  6 357 82.8 4.4  
  Aug 12 2000  140.14 16  7 226 91.2 6.1  
  Aug 12 2120  140.20 24  9 320 71.4 4.0  
  Aug 12 2230  140.24 23 12 398 64.9 3.2  
  Aug 12 2330  140.28 19  9 342 93.8 5.1  
  Aug 13 0030  140.32 19 10 368 83.0 4.3  
  Aug 13 0150  140.38 13  6 423 103.2 5.0  
  Aug 13 0800  140.62  3  3 245 52.7 3.4  
  Aug 14 0000  141.26  4  2 77 40.9 4.6  
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We thank all observers who contributed to the compilation of this first impression of the 2001 Perseids: Karl Antier, Jure Atanackov, Michael Boschat, Dustin Brown, Andreas Buchman, Maria Butkovski, Jens Carsen, Audrius Dubietis, Vedrana Dzaja, Shlomi Eini, Petros Georgopoulos, George Gliba, Shelagh Godwin, Cathy Hall, Amir Hasanzadeh, Monika Hevesi, Zoltan Hevesi, Ken Hodonsky, Kamil Hornoch, Maja Hren, Carl Johannink, Javor Kac, Soheil Khoshbin Far, Katia Koleva, Dovile Kraulaidiene, Vedran Krecel, Anna Levina, Mike Linnolt, Hartwig Luthen, Christophe Marlot, Pierre Martin, Huan Meng, Ali Moosazadeh, Umberto Mule' Stagno, Jens Olesen, Alexei Pace, Senka Pintaric, Miguel A. Serra, Yuying Song, Wes Stone, Josep M. Trigo-Rodriguez, Kim S. Youmans, Jure Zakrajsek, Bo Zhou, Jurga Zieniute, and Mia Zuanic. The observers come from the following countries: Bulgaria, Canada, China, Croatia, Denmark, France, Germany, Greece, Hungary, Iran, Israel, Lithuania, Malta, the Netherlands, Slovenia, Spain, the United Kingdom and the United States.