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