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(meteorobs) IMO Shower Circ. Lyrids 2003
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I M O S h o w e r C i r c u l a r
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LYRIDS 2003
The activity of the 2003 Lyrids was slightly below a normal annual level
(ZHR=18), with the maximum as expected at sollong=32.3 degrees. However,
the pre-maximum was not covered by observations. There is still a gap in
observing times from 31.8 to 32.2 degrees of solar longitude (from 10h to
20h UT, April 22, which favors Asian, Near-East sites and Eastern Europe,
to some extent). As by April 24, 13h UT, 15 observers have reported 191
Lyrids, 23 Saggitarids and 298 sporadics in 43.91 observing hours so far.
Summary of 2003 Lyrid activity.
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Date UT Sollong n_ind n_obs nLYR ZHR err(+/-)
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19 Apr 20:43 29.34 1 3 1 1.4 1.0
20 Apr 21:30 30.35 1 4 8 3.7 1.2
21 Apr 21:25 31.32 4 6 19 6.0 1.3
21 Apr 06:01 31.67 2 4 14 11.3 2.9
22 Apr 22:50 32.35 10 15 79 16.7 1.9
22 Apr 01:40 32.47 7 12 69 14.6 1.7
23 Apr 22:20 33.31 1 2 1 5.9 4.2
Solar longitudes refer to equinox J2000.0. n_ind is the number of
individual observers, n_obs is the number of individual observing
periods, nLYR is the number of Lyrids observed. The radiant position
was assumed at alpha=271°, delta=+34°, the population index used was
r=2.2. The expectation value of the ZHR,
ZHR = (1 + sum nLYR) / 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,
cloud coverage and radiant height correction. Error bars are derived
as err=ZHR/sqrt(1+sum nLYR).
We are very grateful to the following observers for their efforts,
impressions and quick reporting of data:
Rainer Arlt (Germany)
Audrius Dubietis (Lithuania)
Darja Golikowa (Germany)
Daniel Gruen (Germany)
Shlomi Eini (Israel)
Shy Halatzi (Israel)
Anna Levina (Israel)
Bert Matous (USA)
Alastair McBeath (UK)
Bruce McCurdy (Canada)
Alex Mikishev (Israel)
Arkadiusz Olech (Poland)
Michel Vandeputte (Belgium)
Kim S. Youmans (USA)
Ilkka Yrjola (Finland)
Information provided by Audrius Dubietis and Rainer Arlt.
2003 April 24, 14h UT, www.imodot net
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