Shower Analysis

New moon on 1 May provided favourable observing conditions for the Eta-Aquarids this year. By 8 May, 19 observers reported 322 Eta Aquarids in 71.02 h net observing time. In general, rather low activity was recorded (ZHRs~30) with an extended 4-day plateau and no apparent maximum.

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.

Two strong activity peaks of the Leonid meteor shower were predicted. The times fell between 03:48 to 04:04 UT for the first one, and between 10:23 to 10:47 UT for the second peak, both on November 19, 2002.

A first activity analysis from the reports of 86 observers, who logged 19443 Leonids, is given below. The ZHR refers to a stellar limiting magnitude of +6.5, a radiant elevation of 90 deg, and counts of single observers. A population index of r=2 was applied, although the inspection of data suggests a large abundance of faint meteors, thus a larger r. The ZHRs would increase likewise.

The peak time of the first maximum is 04:10 UT with ZHR=2350. The second peak is found near 10:50 UT or a few minutes earlier with ZHR=2660. Both peaks occurred later than the predictions by about the same time lapse. The predictions of the Leonid stream model of Vaubaillon (WGN 30:5, 2002) are closest to reality according to this first analysis.

Nearly moon-free conditions permitted numerous valuable observations of the nights around the Perseid maximum. The peak time was 22h30 UT on August 12 if a solar longitude of 140.0 degrees is assumed. This time favoured European sites, but large parts of central Europe suffered from clouds and rain around August 12.

We present a first activity curve of the 2002 Perseids based on the reports of 140 observers from 30 countries as listed below. The averages include only observing periods with a total correction smaller than 8.0 and radiant elevations higher than 10 degrees. Since a number of new observers contributed to the profile, we made use of perception factors based on the total sporadic activity for all individuals. Details about the analysis will be found in an updated article in the October issue of WGN, the Journal of the IMO. This first curve was obtained with a constant populatsion index of r=2.0 and no corrections for the radiant elevation hR other than sin(hR).

Activity profile obtained from the observations of 177 observers from 28 countries. A total of 137146 Leonids was logged.

Originally, the so-called 'preliminary reports' were meant as an immediate information about the observed activity level of major meteor showers based on a limited number of raw data sent to the IMO directly after the observations. This scheme worked well until the number of observers sending their (full) reports promptly increased so that we now reached a point where we receive an (almost) complete global data set within a few days after a major shower maximum. Of course, it is great to see that observers distribute their full data so quickly. This situation, however, implies that the people doing the input work for the IMO data bases will type the data only once. That is, we now have quite a large number of Geminid reports already in the VMDB (while still many Leonid and Geminid reports are coming in). As a further consequence, the present Geminid report is based on a large quantity of data obtained by 44 observers worldwide and it (almost) looks like a global analysis rather than a very preliminary report. This is also the reason for the delay...