Results of the IMO Video Meteor Network - August 2008
=====================================================

August leaves me with mixed impressions. Subjectively I would say, it was 
a poor month (probably because I missed almost the complete Perseid maximum 
because of clouds). However, looking at the network statistics, it couldn't 
have been that poor. After all, there are six cameras with 25 and more 
observing nights, which is only rarely achieved. At some observing sites 
it was overcasted at the Perseid maximum, but there were 22 active cameras 
on August 10/11 and only two observing sites could not provide data in 
that night. In the second half of August the data got more sparse, but even 
then there have been other months with much fewer observations.

So lets have a look at the overall statistics of August 2008. With roughly
2,100 hours of effective observing time, it ranks second after February
this year. Also those 14,000 meteors have only been beaten in August 2007
and October 2006. So it looks is if it was indeed a good month.

With respect to analyses, August was characterised by preparations for the
IMC, where I intended to present a new full analysis of the IMO Video Meteor
Database. To keep the analysis perfectly up to date, all observing data
until end of July 2008 were included - the last of which I received just
a week before the IMC. As in 2006, the analysis was carried out in two steps.

The computationally more demanding first step was to determine all active
radiants (alpha, delta, v_inf) at each solar longitude. Whereas the base
algorithm was left untouched (it was computed, with what probability each
meteor would belong to each possible radiant, these probabilities were
accumulated for each possible radiant, and finally the radiants with highest
probability were selected), I improved the procedure in some details to
make the results even more relevant. Details of these changes can be found
in my IMC presentation at http://www.imonet.org/imc08/imc08ppt.pdf.
Furthermore, the data set (360,000 meteors) had almost doubled compared
to 2006. Still, I could abstain from distributed computing, since I could
employ two IBM x3850 M2 servers with four quad core CPUs each in the test
lab of my company. Running on 30 CPU kernels in parallel, the calculation
was finished in roughly half a week. Once more, the result of the first step
has been made available online (http://www.imonet.org/imc08/radiants.html),
so everyone can look on his own for meteor showers, or can check in case of
suspected activity of an unknown shower, whether the radiant is also found
in the IMO video data.

The second step was to search for radiants with similar parameters in
subsequent solar longitude intervals, and to find meteor shower with longer
activity intervals. This part of the analysis was identical to 2006, so
there is still room for improvement. Contrary to last time, my IMC
presentation did not contain all showers detected, but only the most active
and long-lasting ones. In the following, I would like to present the results
for two typical August showers in detail.

First of all there is the most active shower in the video data - the Perseids.
With almost 18,000 meteors they make up for 5% of the full IMO Video Meteor
Database. The new "Handbook for Meteor Observers" of IMO lists an activity
interval from July 17 to August 24, which is a bit to short. In the video
data, the Perseid radiant shows up on July 9 for the first time, and remains
visible until August 27. As can be seen in the radiant plot (figure 1), the
drift is uniform between July 13 and August 25, i.e. in that time the shower
can be detected with high confidence. The position of the radiants fits well
to the ephemeris in all but the last 5 days - no wonder if you remember that
the list position was derived from our video data as well.


Figure 1: Perseid radiant position derived from nearly 18,000 shower members
(single station) of the IMO Video Meteor Database (red).

The activity profile of the Perseids (figure 2) shows a minor dip on July 19,
but otherwise a gradually but persistent increase. There is a small
pre-maximum on August 7/8, before the rate reduces a bit and reaches a
strong peak on August 12/13. The dip on August 9 is also known to visual
observers, even though the latest long-term activity profile given in the
IMO handbook (green dots) does not show it. The descending Perseid branch
is very steep, such that they are hardly recognizable anymore by August 20.
All in all, the video results fit very well to visual rates from the VMDB.
On the one hand that is due to the large data set. On the other hand it
still remarkable if you remember, that the video profile was derived only
from the number of Perseids and sporadic meteors, recorded with a wide
variety of video cameras. There were no limiting magnitudes, effective
observing times or r-value profiles involved.


Figure 2: Long-term activity profile of the Perseids derived from video data.
The blue dots mark the ZHR profile form the new IMO handbook with an
identical interval length of 2 degree.

For the second typical shower of August, the kappa-Cygnids, the situation
is a bit more tricky. According to the new IMO handbook, they are active
between August 3 and 25. They reach their maximum on August 17 (according
to the table) resp.19 (according to the activity profile in the handbook)
with an ZHR of 2. The radiant is almost stationary all the time. The 2006
video analysis revealed two showers (or two segments of the same shower)
near the expected position and with an activity interval of 20 days, but
with a different radiant drift velocity and direction. The new analysis
suggests that there might in fact be two showers with nearby radiants. Both
of them have a velocity of 23 km/s, i.e. a little less than the list value
of the kappa-Cygnids (25 km/s). 

The primary shower was detected between August 5 and 26 with an overall 
of 870 meteors. In the beginning, the radiant is roughly 10 degree south 
of the expected KCG position (figure 3). The direction of the radiant drift 
is about the expected one, only the drift velocity is much higher. Thus, 
the radiant is nearly at the expected position by the end of the activity 
interval. The activity profile (figure 4) is flat  and shows only on 
August 17 and 24/25 small raisings. The first one fits to the maximum from 
the visual data.

The second shower was detected with about 700 meteors between August 7 and
25. It's radiant is roughly 5 to 10 degree west of the expected KCG position.
The scatter of the individual positions is much higher, but on average to
position of the radiants is almost constant as presented in the IMO handbook.
The maximum of this shower is on August 18 and comparable to the maximum of
the primary shower.


Figure 3: Radiant position of two August meteor showers which fit well to
the kappa-Cygnids.


Figure 4: Long-term activity profile of both August showers. The red line
is the accumulated activity of both, and the blue dots represent the ZHR
profile from the current IMO handbook.

It not possible to give final conclusions for the kappa-Cygnids yet. As
both showers are quite similar in many respects, but differ in radiant
position by about 10 degree, I would currently speak about two branches
of the same shower or an double radiant.
For comparison,  a plot for August 18 based on the same data set was
obtained with the Radiant software. It also shows a double radiant, but
the primary shower is much stronger (figure 5). In fact, the picture
changes significantly if the standard deviation for velocity and position
errors are modified. This underlines that the last word on the kappa-Cygnids
is not yet spoken.


Figure 5: Radiant plot of August 18 (solar longitude 144-146) with the
Radiant software.


1. Observers
============

Code    Name        Place           Camera         FOV    LM Nights Time Meteors
--------------------------------------------------------------------------------
BRIBE Brinkmann   Herne         HERMINE (0.8/6)   55 dg  3 mag 26   97.9 h   513
CASFL Castellani  Monte Baldo   BMH1 (0.8/6)      55 dg  3 mag 15   83.7 h   414
                                BMH2 (0.8/6)      55 dg  3 mag 27  127.4 h   519
CRIST Crivello    Valbrevenna   STG38 (0.8/3.8)   80 dg  3 mag 11   58.6 h   434
ELTMA Eltri       Venezia       MET38 (0.8/3.8)   80 dg  3 mag 15  100.0 h   706
GONRU Goncalves   Tomar         TEMPLAR1 (0.8/6)  55 dg  3 mag 27  187.5 h  1223
                                TEMPLAR2 (0.8/6)  55 dg  3 mag  3   18.0 h   106
HERCA Hergenroth. Tucson        SALSA (1.2/4)     80 dg  3 mag 20  116.6 h   357
HINWO Hinz        Brannenburg   AKM2 (0.85/25)    32 dg  6 mag 13   82.8 h   340
KACJA Kac         Kostanjevec   METKA (0.8/8)     42 dg  4 mag 21  142.8 h   585
                  Kamnik        REZIKA (0.8/6)    55 dg  3 mag 12   80.4 h   935
                  Ljubljana     ORION1 (0.8/8)    42 dg  4 mag 29  162.8 h   870
                                ORION2 (0.8/8)    42 dg  4 mag  4   25.4 h   610
LUNRO Lunsford    Chula Vista   BOCAM (1.4/50)    60 dg  6 mag  9   36.0 h   808
MOLSI Molau       Seysdorf      AVIS2 (1.4/50)    60 dg  6 mag 13   52.2 h  1055
                                MINCAM1 (0.8/6)   55 dg  3 mag 27  124.3 h   516
                  Ketzuer       REMO1 (0.8/3.8)   80 dg  3 mag 23   97.8 h   693
                                REMO2 (0.8/3.8)   80 dg  3 mag 25  100.0 h   742
SLAST Slavec      Ljubljana     KAYAK1 (1.8/28)   50 dg  4 mag 15   88.3 h   284
STOEN Stomeo      Scorze        MIN38 (0.8/3.8)   80 dg  3 mag 16  108.0 h   593
STRJO Strunk      Herford       MINCAM2 (0.8/6)   55 dg  3 mag 21   63.1 h   300
                                MINCAM3 (0.8/8)   42 dg  4 mag 17   61.5 h   273
                                MINCAM5 (0.8/6)   55 dg  3 mag 19   61.1 h   426
WEBMI Weber       Chouzava      TOMIL (1.4/50)    50 dg  6 mag  5   11.1 h   272
YRJIL Yrjola      Kuusankoski   FINEXCAM (0.8/6)  55 dg  3 mag 13   68.6 h   221
--------------------------------------------------------------------------------
Sum                                                            31 2155.4 h 13785


2. Observing Times (h)
======================

Aug    01   02   03   04   05   06   07   08   09   10   11   12   13   14   15
--------------------------------------------------------------------------------
BRIBE  6.3  0.3   -   4.8  1.8  5.5  2.1  3.7   -   5.9  1.8  7.9  8.0  7.4  7.0
CASFL   -   4.9  7.2  7.3   -    -   6.5  6.0  7.6  7.6  7.7  3.6  1.0   -    - 
        -   3.9  3.5  7.3  0.5   -   2.8  7.5  7.6  7.6  6.5  4.6  2.9   -    -
CRIST   -   6.0   -    -    -    -    -   4.2  7.5  7.6  7.4   -    -   0.5  6.7
ELTMA  4.2  7.3  7.2  7.5  5.0   -   7.6   -   6.5  7.6  7.3  7.5   -    -    -
GONRU   -    -    -   7.0  7.6  6.0  7.7  8.1  8.0   -   2.3  7.9  8.2  8.2  1.6
        -    -    -    -   6.6  4.2   -    -   7.2   -    -    -    -    -    -
HERCA  5.2  6.3  5.7   -   2.6  4.5  7.9  2.3  8.7  5.4  8.6  7.0  8.0   -    -
HINWO   -   0.6   -    -   6.6  3.3   -    -   5.1  4.5  23    -    -    -    -
KACJA   -   4.5  7.4   -    -   7.0  7.5   -   7.5  7.4  7.7  7.5   -   7.6   - 
        -    -    -    -    -    -   6.3   -   6.9  6.8  6.3   -   1.1   -    - 
       3.8  5.2  7.5  1.3  0.3  7.6  7.6  0.9  7.7  7.8  7.9  7.4  1.9  5.9   - 
        -    -    -    -    -   4.6   -    -   5.8  7.2  7.8   -    -    -    -
LUNRO   -   2.5   -    -    -    -    -   6.8  5.6  7.6  3.5  6.0   -    -    -
MOLSI   -    -    -    -    -   5.0  1.2  0.5   -    -    -    -   4.9  1.3   - 
        -   1.4  6.1  1.2  7.2  7.3  1.8  4.9  4.5  7.5  0.2   -   1.7   -   0.3
        -    -   2.8  6.4  6.4  6.4  2.5  3.7  5.3  5.0   -   2.5  7.0  4.1  3.7
        -   0.7  3.3  6.4  6.5  6.4  2.4  3.2  5.8  3.5   -   2.6  6.5  5.7  1.3
SLAST  3.5  5.6  6.7   -    -    -    -    -   4.8  7.1  7.3  7.3   -   5.0   -
STOEN  2.7  7.0  7.1  6.1  5.3   -   7.2   -   7.3  7.4  7.5  7.5   -    -    -
STRJO   -    -    -   4.1  2.4  5.7  1.1  2.9   -   4.5   -   3.3  4.3  1.6  2.7
        -    -    -   4.4  0.8  5.7  2.0  3.7   -   4.7   -   0.5  5.2  3.2  5.4
       3.4   -    -   3.7  1.3  5.1  2.3  3.8   -   2.7   -   3.4  4.6  2.2  5.5
WEBMI   -    -    -    -    -   2.4   -    -    -   1.4   -    -   1.8   -    -
YRJIL   -   2.9   -   3.0  32    -    -    -   3.6  2.7  3.0   -    -    -   2.5
--------------------------------------------------------------------------------
Sum   29.1 59.1 64.5 70.5 92.9 86.7 76.5 62.2123.0129.5115.8 86.5 67.1 52.7 36.7

Aug    16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   31
-------------------------------------------------------------------------------------
BRIBE  4.6  0.3  5.0  2.3  5.4  0.8  1.2  2.8   -   2.2  0.3   -    -   3.6  5.2  1.7
CASFL   -   7.9  8.1   -    -    -    -    -    -    -    -    -    -   4.3  3.2  0.8
       0.5  7.0  7.6  2.8  5.2  4.8  7.3  2.5  5.9  7.0  4.5  3.6  5.1  6.7  1.7  0.5
CRIST  1.1  2.1   -    -    -    -    -   7.0   -    -    -    -    -    -   8.5   -
ELTMA  2.3  6.0   -   8.0   -   8.1   -    -   7.9   -    -    -    -    -    -    -
GONRU  7.1  8.2  6.5  8.2  8.7  5.0  8.8  7.5  6.5  3.9  3.7  8.9  9.0  4.7  9.0  9.2
        -    -    -    -    -    -    -    -    -    -    -    -    -    -    -    -
HERCA  7.2  2.0   -    -    -    -   8.2  6.7  8.3  3.2   -    -   4.2   -   4.6   -
HINWO  6.6  4.8  5.9   -    -    -    -    -    -    -   5.6  5.5   -   3.1  8.2   -
KACJA  5.1   -   5.8  6.2   -   8.3  6.1   -   8.5  5.1  7.9  8.5  5.4  5.1   -   6.7
        -    -   6.9  8.1   -    -   6.1   -   8.5   -   8.6  7.3  7.5   -    -    - 
       3.1  4.9  7.2  8.3  0.8  4.5  8.4   -   6.8  8.6  8.6  8.6  7.1  6.8  0.8  5.5
        -    -    -    -    -    -    -    -    -    -    -    -    -    -    -    -
LUNRO  1.0   -    -   1.0  2.0   -    -    -    -    -    -    -    -    -    -    -
MOLSI   -   1.5   -    -    -    -    -   1.6   -   4.5  6.8  6.2  4.9  5.8  8.0   - 
       7.9  5.4  7.0   -   4.2  4.2  0.4  2.3  8.4  6.6  8.5  8.6  5.6  4.2  6.4  0.5
       0.7  6.2  1.4  0.3  3.9  4.0   -   3.8   -    -    -    -   0.3  4.2  8.3  8.4
        -   6.7  1.4  3.8  4.4  3.3   -   3.8   -   0.6   -   1.2  0.2  3.7  8.3  8.3
SLAST   -    -    -    -    -    -    -    -   6.4  8.7  8.1   -   8.6  6.4  0.9  1.9
STOEN   -    -   7.9   -   1.9  8.2   -    -   8.1  8.3   -    -   8.5   -    -    -
STRJO  1.2  0.5  1.0  1.3   -   1.2   -   4.6   -   3.5  0.2   -    -   7.9  6.9  2.2
       4.7  0.5  2.2  2.2   -    -    -    -    -   0.5   -    -    -   7.9  7.9   - 
       4.8  0.3  0.5  0.5   -    -    -    -    -   0.8   -    -    -   7.1  6.9  2.2
WEBMI   -    -    -    -    -    -    -    -    -    -   2.5  2.0   -    -    -   1.0
YRJIL   -    -    -   3.7   -   0.4  4.3  4.6   -    -    -    -    -    -   2.0  3.9
-------------------------------------------------------------------------------------
Sum   57.9 64.3 74.4 56.7 36.5 52.8 50.8 47.2 75.3 63.5 65.3 60.4 66.4 81.5 96.8 52.8


3. Results (Meteors)
====================

Aug    01   02   03   04   05   06   07   08   09   10   11   12   13   14   15
--------------------------------------------------------------------------------
BRIBE  23    2    -   20    8   25    7   13    -   23   11  106   79   31   34
CASFL   -   32   36   33    -    -   23   25   37   58   59   31    9    -    - 
        -   15   13   33    4    -   11   48   41   55   51   62   17    -    -
CRIST   -   31    -    -    -    -    -   49   70   72   78    -    -    4   39
ELTMA  24   47   46   42   13    -   40    -   39   66  126  140    -    -    -
GONRU   -    -    -   26   46   14   45   90   83    -   19  149   79   73    7 
        -    -    -    -   54   18    -    -   34    -    -    -    -    -    -
HERCA  11   32   19    -    5    8   34    6   18   25   35   35   30    -    -
HINWO   -    2    -    -   56   23    -    -   34   28   22    -    -    -    -
KACJA   -   17   29    -    -   33   29    -   29   51   74  104    -   26    - 
        -    -    -    -    -    -   78    -   81  143  202    -   11    -    - 
       10   13   39    6    1   45   43    1   52   87  140  134   14   17    - 
        -    -    -    -    -   76    -    -  101  179  254    -    -    -    -
LUNRO   -   13    -    -    -    -    -   56   52   81  212  383    -    -    -
MOLSI   -    -    -    -    -  142   15   12    -    -    -    -  154   11    - 
        -    5   40    1   35   42   13   17   21   82    1    -    7    -    2 
        -    -   12   45   62   45   12   38   46   54    -   30  122   24   39 
        -    2   17   43   69   68   12   41   51   25    -   54  125   40    8
SLAST   5   12   20    -    -    -    -    -   11   32   48   70    -   10    -
STOEN  11   36   33   36   18    -   26    -   39   65  134   63    -    -    -
STRJO   -    -    -   21    5   31    3   16    -   25    -   64   33    5    8 
        -    -    -   16    2   20    5   18    -   29    -   13   49    8   28 
       27    -    -   27    5   26    6   39    -   13    -  123   63    9   27
WEBMI   -    -    -    -    -   83    -    -    -   85    -    -    -    -    -
YRJIL   -    2    -   24   27    -    -    -   15   27   39    -    5    -   13
-------------------------------------------------------------------------------
Sum   111  261  304  373  410  699  402  469  854 1305 1505 1561  797  258  205

Aug    16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   31
------------------------------------------------------------------------------------
BRIBE  18    1   15   10   13    3    4   13    -    7    1    -    -   19   19    8
CASFL   -   25   30    -    -    -    -    -    -    -    -    -    -    6    8    2 
        1   20   30    7   10   12   11   14   10   15    7    5   11   13    2    1
CRIST  14   17    -    -    -    -    -   33    -    -    -    -    -    -   27    -
ELTMA   6   30    -   28    -   35    -    -   24    -    -    -    -    -    -    -
GONRU  27   63   38   56   48   15   51   38   37    8    9   53   38   13   33   65 
        -    -    -    -    -    -    -    -    -    -    -    -    -    -    -    -
HERCA  16   14    -    -    -    -   19   11   18    7    -    -    7    -    7    -
HINWO  22   14   32    -    -    -    -    -    -    -   25   16    -    9   57    -
KACJA  10    -   17   12    -   17   16    -   34    9   27   19   12    8    -   12 
        -    -   52   45    -    -   49    -   80    -   78   66   50    -    -    - 
        8   20   26   27    3    9   28    -   23   28   25   25   19   12    2   13 
        -    -    -    -    -    -    -    -    -    -    -    -    -    -    -    -
LUNRO   2    -    -    4    5    -    -    -    -    -    -    -    -    -    -    -
MOLSI   -    8    -    -    -    -    -   24    -   69  142  135   56  134  153    - 
       27   26   30    -   22    9    3    8   21   16   23   22    5   12   23    3 
        3   36    6    1    9   12    -   12    -    -    -    -    1   17   44   23 
        -   26    9    7   12   18    -   16    -    4    -    1    1   17   52   24
SLAST   -    -    -    -    -    -    -    -    7   18   16    -   16   13    2    4
STOEN   -    -   40    -    2   18    -    -   26   25    -    -   21    -    -    -
STRJO   3    2    3    5    -    3    -   20    -    7    1    -    -   20   16    9 
       21    1    6    7    -    -    -    -    -    2    -    -    -   20   28    - 
       16    1    1    2    -    -    -    -    -    2    -    -    -   13   20    6
WEBMI   -    -    -    -    -    -    -    -    -    -   43   50    -    -    -   11
YRJIL   -    -    -    8    -    1   20   20    -    -    -    -    -    -    5   15
------------------------------------------------------------------------------------
Sum   194  304  335  219  124  152  201  209  280  217  397  392  237  326  498  196

Sirko Molau, 2008/10/08