Lyrids 2001

Very favourable lunar conditions made this shower a highlight
target of 2001. Occasionally heightened activity is observed
from the Lyrids, most notably in 1982. The 2001 maximum exhibited
a slightly enhanced level of activity. Observations from
49 observers were collected by April 24, 0h UT. Such a large
number of observations monitoring a shower of moderate activity
is a fairly nice success of amateur meteor observing. The
table of the activity graph is given below.

The maximum is broad; highest rates are found near a solar
longitude of lambda = 32.0° with ZHR = 33±3. The first
peak at lambda = 31.7° comprises a number of novice observers
who may have underestimated their limiting magnitudes. Nevertheless,
the up-and-down or — more roughly speaking — the
general plateau shape of the activity profile appears to be
a typical feature of the 2001 Lyrids. This was already found
in recent Lyrid activity profile. This year, the plateau may
extend over as much as 24 hours. ZHRs in 2000 were lower, 20
at best, in 1999 near 30 as this year, but again significantly
lower in 1998 with values below 20.

  
  ----------------------------------------------------------  
  2001 Time Sollong  nObs nIND nLYR ZHR +/-  
  Apr (UT) (J2000)  
  ----------------------------------------------------------  
  17  0620  27.295  2  1  0  3  3  
  19  0600  29.237  1  1  0  7  7  
  20  0130  30.030  1  1  3  3  2  
  20  2200  30.864  6  2  13  5  1  
  21  0140  31.013  8  5  30  8  1  
  21  1800  31.678  8  7  85  37  4  
  21  2130  31.820  18 13 155  28  2  
  21  2320  31.894  13 13  67  18  2  
  22  0000  31.922  10 10 128  28  2  
  22  0100  31.962  14 12 117  19  2  
  22  0230  32.023  10 10  90  33  3  
  22  0900  32.287  8  5  54  27  4  
  22  2130  32.795  3  2  19  24  5  
  23  2200  33.791  2  2  7  8  3  
  ----------------------------------------------------------  
  

Solar longitudes refer to equinox J2000.0. nObs is the number
of individual observing periods, nIND is the number of individual
observers providing them, nLYR is the number of Lyrids
seen. The radiant position was assumed at alpha=271°, delta=+34°,
the population index used was r=2.9. 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, clouds, and zenith correction. Times are rounded to
the nearest 10 minutes.

We are very grateful to the following observers for their
efforts and quick reporting of data:

ANTDU Dusan Antic (Serbia), MENHU Huan Meng (China),
ARLRA Rainer Arlt (Germany), MILAA Ana Milovanovic (Serbia),
BASLU Luc Bastiens (Belgium), MISKO Koen Miskotte (Netherlands),
BETFE Felix Bettonvil (Netherlands), MODAM Amruta Modani (India),
BHANE Neha Bhandari (India), NISMA Markku Nissinen (Finland),
BHASU Sushrut Bhanushali (India), PATSO Sonali Patil (India),
DECGO Goedele Deconink (Belgium), PEEBJ Bjorn Peeters (Belgium),
DEOPA Parag Deotare (India), PRAMA Mayuresh Prabhune (India),
DUBAU Audrius Dubietis (Lithuania), PUNNI Nilesh Puntambekar (India),
FANYU Yuwei Fan (China), RENJU Juergen Rendtel (Germany),
GADSH Shirish Gadkar (India), SAVBR Branislav Savic (Serbia),
GEOPE Petros Georgopoulos (Greece), SONWA Wanfang Song (China),
GEYBE Benny Geys (Belgium), SUNHU Huiming Sun (China),
GLIGE George Gliba (USA), TRIJO Josep Trigo-Rodriguez (Spain),
GOLDA Darja Golikowa (Germany), TUKAR Arnold Tukkers (Netherlands),
HASTA Takema Hashimoto (Japan), UCHSH Shigeo Uchiyama (Japan),
JOHCA Carl Johannink (Netherlands), VELKR Kristina Veljkovic (Serbia),
KULMA Manali Kulkarni (India), VERJN Jan Verbert (Belgium),
KULRH Rhikesh Kulkarni (India), VUJKA Katarina Vujic (Serbia),
KULVI Vineet Kulkarni (India), VUJRO Romana Vujasinovic (Serbia),
LANMA Marco Langbroek (Netherlands), WANSH Shuo Wang (China),
LINMI Mike Linnolt (USA), WISJE Jean-Marc Wislez (Belgium),
LUNRO Robert Lunsford (USA), ZERZO Zorana Zeravcic (Serbia),
MARAN Antonio Martinez (Venezuela), ZHUJI Jin Zhu (China),
MCBAL Alastair McBeath (UK) and ZUPLJ Ljubica Zupunski (Serbia).