Subject: (meteorobs) IMO Meteor Shower Circular - 2001 Perseids
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International Meteor Organization
Meteor Shower Circular
2 0 0 1 P E R S E I D S
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compiled by Marc Gyssens en Vladimir Kroumov
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Abstract: The 2001 Perseids were characterized by a
broad and
fairly flat plateau of maximum activity between Aug 12,
9h UTC
and the early UTC hours of Aug 13, with a ZHR around
85. Due
to the scatter in individual data caused by poor
observing
conditions, it is not possible to identify individual
peaks
within this time interval in this stage of the data
collection.
Such peaks cannot be very outspoken, however.
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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, but 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 Visual Commission Director
Rainer Arlt at
rarlt@a... (the alias "visual@i..." does NOT work
momentarily!).
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Date Time(UTC)Sollong nObs nInd nPER ZHR +/-
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Jul22 0000 119.25 7 3 14 5.8 1.5
Jul27 0000 124.03 4 1 8 3.7 1.2
Jul28 0000 124.98 20 7 49 5.7 0.8
Jul29 0000 125.94 5 2 13 3.7 1.0
Jul30 0000 126.90 7 2 21 5.4 1.2
Aug07 2100 135.39 3 1 8 13.2 4.3
Aug09 0000 136.47 5 1 12 12.6 3.5
Aug11 0000 138.38 6 6 81 37.4 4.1
Aug11 1430 138.96 6 3 79 66.9 7.4
Aug11 2115 139.23 16 13 233 46.1 3.0
Aug11 2230 139.28 15 12 273 45.1 2.7
Aug11 2330 139.32 14 10 192 61.3 4.4
Aug12 0050 139.38 15 10 223 69.4 4.6
Aug12 0150 139.42 13 9 297 55.8 3.2
Aug12 0415 139.51 10 5 175 54.5 4.1
Aug12 0900 139.70 13 6 357 82.8 4.4
Aug12 2000 140.14 16 7 226 91.2 6.1
Aug12 2120 140.20 24 9 320 71.4 4.0
Aug12 2230 140.24 23 12 398 64.9 3.2
Aug12 2330 140.28 19 9 342 93.8 5.1
Aug13 0030 140.32 19 10 368 83.0 4.3
Aug13 0150 140.38 13 6 423 103.2 5.0
Aug13 0800 140.62 3 3 245 52.7 3.4
Aug14 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 Butpovski, 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
from Bulgaria, Canada, China, Croatia, Denmark, France,
Germany, Greece, Hungary, Iran, Israel, Lithuania,
Malta,
the Netherlands, Slovenia, Spain, the United Kingdom,
and
the United States.
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International Meteor Organization, August 15, 2001. |