Leonids 2003

An updated profile of the Leonid meteor activity was computed.
The data collected are still producing a noisy picture. An
enhancement of activity is found on November 13, between
12h UT and 24h UT. This coincides with the predicted encounter
time with the 1499 dust trail of Comet 55P/Tempel-Tuttle.

The clearest feature of the profile is the activity maximum
on November 19, between 0h UT and 22h UT. No sharp peak time
is found. Predictions were given for the 1533 dust trail encounter between 6h30 and 8h UT. The predictions mentioned are
based on calculations by Asher, Lyytinen, Nissinen, McNaught,
and Vaubaillon.

Lyytinen obtained additionally an encounter with the 1733 trail
for November 19, 16h50 UT. The long duration of the observed
November 19 peak maybe attributed to the superposition of the
two encounters. Data are not sufficient though to derive
more precise peak times.

  
  --------------------------------------------------------  
  Date (UT) Time Solarlong nINT nLEO ZHR +/-  
  --------------------------------------------------------  
  Nov 13.05 01:12 230.184  3  9  14  4  
  Nov 13.50 12:00 230.637  4  13  27  7  
  Nov 13.67 16:05 230.808  12  15  13  3  
  Nov 13.73 17:31 230.868  17  59  21  3  
  Nov 13.78 18:43 230.918  12  50  19  3  
  Nov 14.01 00:14 231.150  7  9  22  7  
  Nov 14.77 18:29 231.915  1  2 (41) 24  
  Nov 15.71 17:02 232.861  6  8  15  5  
  Nov 15.80 19:12 232.952  7  20  16  3  
  Nov 16.67 16:05 233.828  16  38  14  2  
  Nov 17.37 08:53 234.534  8  16  13  3  
  Nov 17.72 17:17 234.887  17  65  18  2  
  Nov 18.44 10:34 235.613  13  42  15  2  
  Nov 19.03 00:43 236.208  14  91  40  4  
  Nov 19.11 02:38 236.289  13 111  41  4  
  Nov 19.17 04:05 236.349  14  96  32  3  
  Nov 19.26 06:14 236.440  6  16  39  9  
  Nov 19.34 08:10 236.521  13  69  27  3  
  Nov 19.42 10:05 236.601  12 117  35  3  
  Nov 19.63 15:07 236.813  23 292  63  4  
  Nov 19.91 21:50 237.096  19  51  43  6  
  Nov 20.20 04:48 237.389  18 171  32  2  
  Nov 20.92 22:05 239.126  8  21  14  3  
  Nov 21.66 15:50 238.863  11  40  7  1  
  Nov 22.18 04:19 239.388  7  17  10  2  
  Nov 22.91 21:50 240.126  8  26  11  2  
  Nov 23.15 03:36 240.369  7  28  6  1  
  --------------------------------------------------------  
  

A population index of r=2.3 was used to extrapolate to lm=+6.5.
All solar longitudes refer to equinox J2000.0. nINT is the
number of observing periods, nLEO the number of Leonid meteors.

Many of the observations suffer from low limiting magnitudes,
and the value of the limiting magnitude may be systematically
over- or underestimated. We derived the median of the sporadic
hourly rates of all the observing periods and obtain <HR> = 16
which is typical for November. Observers reporting at least
10 sporadics meteors are corrected according to the ratio of
their average sporadic rate to 16.