Results of the AKM Video Meteor Network - December 2000 ======================================================= December was a worthy final of a successful year of video observations. There were long periods of bad weather at the middle and end of month, but the large number of active observers and long winter nights compensated for that. In the end, December was on the third place (after August and September) with respect to the effective observing time, and ranked even second (after August) with respect to the number of meteor records. The highlight of December is usually the Geminid maximum - not so in 2000! This shower was not only hampered by the moon, but fell literally into the (rain) water. Of special interest, however, were the Ursids. Only weeks before their maximum an outburst was predicted for the morning of December 22. Fortunately enough, skies were clear over much of central Europe, resulting in large numbers of visual and video observations that night. By now the picture is still contradictory. There are observations showing no enhanced activity, whereas others claim to see the outburst in their data. Our video cameras also recorded largely increasing Ursid activity towards dawn of the night in question. Not included in this statistics are three observing session of Andre Knoefel. Due to an error in the measurement of reference stars we had to remove his 15.3h effective observing time and 44 meteors from the database. By now the problem should be fixed. Overall, the last year was a very successful one for the video observers in the German Arbeitskreis Meteore. 8 (1999: 5) observers recorded in 239 (1999: 120) nights and 2301.3 hours (1999: 1002.4) effective observing time an overall of 11,659 (1999: 6,476) meteors. In other words: The outcome of last year could be doubled. 239 observing nights is a coverage of almost 2/3 of the year! There are three camera stations (Aachen, Dresden, Marquardt) which supplied observations in all twelve months. The other stations were only part-time operated. About 1/3 of the observing time was supplied by Juergen Rendtel and Sirko Molau, the last third was contributed by the remaining observers. Ulrich Sperberg had to give up already in January when his image intensifier broke down. As soon as the new AKM video cameras will be ready, his station Salzwedel will become active again. Because of poor camera parameters, the video system of Detlef Koschny recorded only very few meteors in the first months. In August, however, it got a new fast wide-angle lens and yielded similar detection rates as the other cameras from then on. Table 1 gives the detailed statistics of operation times for all participating video observers. RENJU and MOLSI operated their systems in virtually every clear night, even if skies cleared only briefly. Hence, the different number of observing nights reflects better weather conditions especially in the cold months in east Germany. On the other hand, the image intensifier of AVIS is more powerful than that of CARMEN, resulting in a better limiting magnitude and more meteor records. Whereas CARMEN detected an average of 3.8 meteors per hour, it was 6.3 meteors per hour for AVIS. Table 1: Operation Times of the AKM Video Cameras 2000 Observer Camera Primary Site Nights Time [h] Meteors --------------------------------------------------------------------- Juergen Rendtel CARMEN Marquardt 158 811.7 3,085 Sirko Molau AVIS, ESCIMO Aachen 146 709.9 4,507 Mirko Nitschke VK1, VK2 Dresden 62 290.6 2,021 Ilkka Yrjola NONAME Kuusankosi 34 172.5 631 Joerg Strunk FAMOS Leopoldshoehe 26 149.0 858 Detlef Koschny ICC Noordwijkerhout 20 113.2 386 IAP team IAP1 Kuehlungsborn 4 38.3 139 Ulrich Sperberg ADAM Salzwedel 2 16.1 32 --------------------------------------------------------------------- Overall 239 2301.3 11,659 Table 2 shows the monthly distribution of observations. Ignoring August, the number of cameras operated each month was almost constant. The main weather situation is best reflected by the observing time: March and July provided extremely poor conditions, whereas in April and since August 20 and more nights could be used for observations each month. On top of the list are August and September. The Perseids are well reflected in the number of meteor records. However, there is some bias since during major meteor showers more cameras than usual are operated. The last column gives the average number of meteors per hour for the two cameras operated in every clear night (AVIS, CARMEN). Here we can clearly see the annual variations in meteor activity. The year starts relatively slow (the Quadrantids 2000 were clouded out). Shortly thereafter meteor actitivy reaches it's absolute minimum without any major shower in February and March. Despite the Lyrids not much happens in April. The May data are biased by our eta-Aquarid expedition to Jordan, but at least in June increasing meteor activity becomes evident. Due to the short nights, this is not reflected in the absolute meteor counts, however. By July activity has reached the all-year average thanks to a number of minor showers, and briefly thereafter we have the annual maximum in August caused by the Perseids and their long activity period. Meteor counts drop briefly in September, but recover in October again thanks to the Orionids, Taurids, and increased sporadic rates. The remainder of the year stays active, even though we missed both the maxima of the Leonids and Geminids in 2000. The net effect of all factors (duration of night, global weather situation, meteor activity) is that more than 80% of all meteors were recorded in the second half of the year. Our video data show also clearly the daily variations in meteor activity. On long winter evenings it may happen, that there is not one meteor detected in one hour, whereas in the morning hours there are typically more than ten meteors per hour. Table 2: Monthly Distribution of Video Meteor Observations 2000 Month Cam Nights Time Meteors Met/Hour --------------------------------------------- January 5 17 190.8 679 3.2 February 3 16 137.1 391 2.8 March 4 9 52.4 101 2.0 April 5 21 182.4 429 2.4 May 4 19 107.4 342 3.4 June 3 19 93.5 286 3.2 July 5 14 60.5 339 5.1 August 8 27 342.2 2,997 8.6 September 5 28 339.2 1,601 4.9 October 5 20 217.3 1,321 6.5 November 6 25 259.9 1,354 5.3 December 5 24 318.6 1,819 6.4 ---------------------------------------------- Overall 10 239 2301.3 11,659 5.0 1. Observers ============ Code Name Place Camera FOV LM Nights Time Meteors -------------------------------------------------------------------------------- KOSDE Koschny Noordwijkerhout ICC4 (0.85/25) 25 dg 6 mag 8 54.2 h 184 MOLSI Molau Aachen AVIS (2.0/35) 40 dg 5 mag 11 79.6 h 697 NITMI Nitschke Dresden VK1 (0.75/50) 20 dg 8 mag 8 36.3 h 209 RENJU Rendtel Marquardt CARMEN (1.8/28) 28 dg 5 mag 18 96.0 h 428 STRJO Strunk Leopoldshoehe FAMOS (2.0/28) 45 dg 5 mag 4 42.9 h 242 -------------------------------------------------------------------------------- Overall 24 309.0 h 1760 2. Observing Times (h) ====================== Dec 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 -------------------------------------------------------------------------------- KOSDE - - 10.5 6.2 - 7.0 - - 3.9 - - - - - - MOLSI - - 5.9 10.3 - 7.4 - - - - - - - - - NITMI 5.1 - - - 5.1 4.1 - - - - - - 1.6 - - RENJU - 5.0 1.5 3.0 12.0 9.0 0.7 3.0 6.5 - - - 1.1 1.5 1.5 STRJO - - - - - - - - - - - - - - - --------------------------------------------------------------------------------- Sum 5.1 5.0 17.9 19.5 17.1 27.5 0.7 3.0 10.4 - - - 2.7 1.5 1.5 Dec 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 ------------------------------------------------------------------------------------- KOSDE - 5.9 - - - 0.6 9.6 - - 10.5 - - - - - - MOLSI - 1.9 - 6.2 13.5 11.9 6.5 1.7 - - - - 6.6 - - 7.7 NITMI - - - - 5.1 5.1 5.1 - - - - 5.1 - - - - RENJU - - 5.8 - - 8.6 13.0 1.8 - - - - 9.2 7.4 - 5.4 STRJO - - - - 12.2 12.2 12.6 - - - - - 5.9 - - - ------------------------------------------------------------------------------------- Sum - 7.8 5.8 6.2 30.8 38.4 46.8 3.5 - 10.5 - 5.1 21.7 7.4 - 13.1 3. Results (Meteors) ==================== Dec 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 -------------------------------------------------------------------------------- KOSDE - - 52 28 - 37 - - 6 - - - - - - MOLSI - - 82 52 - 86 - - - - - - - - - NITMI 40 - - - 28 30 - - - - - - 7 - - RENJU - 6 12 6 93 30 1 28 26 - - - 3 1 4 STRJO - - - - - - - - - - - - - - - -------------------------------------------------------------------------------- Sum 40 6 146 86 121 183 1 28 32 - - - 10 1 4 Oct 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 ------------------------------------------------------------------------------------- KOSDE - 12 - - - 1 24 - - 24 - - - - - - MOLSI - 11 - 57 76 116 20 2 - - - - 99 - - 96 NITMI - - - - 25 35 37 - - - - 7 - - - - RENJU - - 15 - - 51 34 3 - - - - 61 14 - 40 STRJO - - - - 63 103 64 - - - - - 12 - - - ------------------------------------------------------------------------------------- Sum - 23 15 57 164 306 179 5 - 24 - 7 172 14 - 136 Sirko Molau, 2001/01/11