Results of the IMO Video Meteor Network - May 2009
==================================================

The weather in May was not record-breaking, but better than average. 12 out 
of 32 cameras recorded meteors in 20 or more nights, and in total we collected 
almost exactly 2,000 hours of effective observing time. The 5,000 recorded 
meteors are in particular valuable, because most observers suffer from the 
short northern hemisphere nights and the low overall activity at that time 
of year. Thus, May and June are still the months with the smallest overall 
data set.

Looking at the list of meteor showers in May, we find with the eta-Aquariids 
the strongest source of the southern hemisphere, and with the eta-Lyrids a
minor shower that was only 2007 included into the IMO meteor shower list, 
beside the always active antihelion source. From the analysis perspective, 
the eta-Aquariids are particularly interesting. At the mid-northern latitudes, 
where most video observers are currently active, they are hardly to observe 
because the radiant rises only shortly before sunrise. Typically one will 
catch only a handful of shower members at dawn of the shower maximum. When 
the observability function is applied to correct for the observing geometry,
each eta-Aquariid observed at 48° N gets a weight of 30 - that's about twenty 
time as much weight as a Geminid in mid-December would get. Hence, only small 
scatter or systematic deviations will have a tremendous impact on the meteor 
shower activity. Still, the obtained activity profile gives quite a consistent 
picture.

The meteor shower analysis presented at the 2008 IMC revealed an activity 
interval of the eta-Aquariids between April 27 and May 18, based on a thousand 
shower members (figure 1). The interval is clearly shorter than the one given 
in the IMO working list, but the activity is above ten between April 28 and 
May 15. That hints on possible extended meteor shower activity beyond the
limits given here. The determined meteor shower velocity of 67 km/s agrees
well with the value from literature (66 km/s) and also the radiant position
is confirmed by our video observations. Only the amount of the radiant drift
is smaller than expected.


Figure 1: Radiant position of the eta-Aquariids from data of the IMO Video
Meteor Database.

Figure 2 depicts the activity profile of the eta-Aquariids. The blue dots
represent the long-term activity profile obtained from visual observations,
averaged over two degrees solar longitude. Both graphs match remarkably well,
in particular if the large correction factors are taken into consideration.
According to the video data, the maximum occurs at 47° solar longitude,
about 1.5 days later than in the visual data. However, there is a plateau of
high activity early May, which is why the time of maximum may vary easily.


Figure 2: Long-term activity profile of the eta-Aquariids. The blue dots
represent the profile obtained from visual data.

The eta-Lyrids, the second shower of May, can be identified between May 7
and 14 based on 260 shower members. Their activity interval starts later but
last also somewhat longer than given in the IMO meteor shower list. The
radiant position (Figure 3) agrees well with the value from literature, but
there is no clear radiant drift in the full activity interval. It rather
seems that the radiant is stationary. The velocity of 43 km/s determined
from the video data agrees once more well with the value from the IMO meteor
shower list (44 km/s).


Figure 3: Radiant position of the eta-Lyrids from data of the IMO Video
Meteor Database.

The activity profile (Figure 4) is symmetric and reaches a maximum of about 2 
at May 11. The IMO handbook gives a value of three around May 8. However, 
at such low rates the maximum date derived from video data is more reliable. 
Also here we may have another look at the observability function: As the 
eta-Lyrid radiant is high in the sky all night long, the correction factor 
is one order of magnitude smaller than that of the eta-Aquariids. That 
reflects also in the plain meteor counts. Even though their activity interval 
is more than twice as long and the maximum rate even a factor of 25 higher, 
the total number of eta-Aquariids recorded so far is only a factor of four 
larger than the number of eta-Lyrids. 


Figure 4: Long-term activity profile of the eta-Lyrids.


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

Code    Name        Place           Camera         FOV    LM Nights Time Meteors
--------------------------------------------------------------------------------
BENOR Benitez-S.  Las Palmas    TIMES5 (0.95/50)  10 dg  3 mag  3    4.9 h     6
BRIBE Brinkmann   Herne         HERMINE (0.8/6)   55 dg  3 mag 25   72.3 h   214
CASFL Castellani  Monte Baldo   BMH1 (0.8/6)      55 dg  3 mag 18   42.6 h    82
                                BMH2 (0.8/6)      55 dg  3 mag 19   62,3 h    96
CRIST Crivello    Valbrevenna   C3P8 (0.8/3.8)    80 dg  3 mag 27  141.8 h   340
ELTMA Eltri       Venezia       MET38 (0.8/3.8)   80 dg  3 mag  3    9.5 h    17
GONRU Goncalves   Tomar         TEMPLAR1 (0.8/6)  55 dg  3 mag 22  144.7 h   414
                                TEMPLAR2 (0.8/6)  55 dg  3 mag 13  100.2 h   230
GOVMI Govedic     Sredisce      ORION2 (0.8/8)    42 dg  4 mag 12   59.1 h   169
HERCA Hergenroth. Tucson        SALSA (1.2/4)     80 dg  3 mag 26  133.9 h   195
HINWO Hinz        Brannenburg   AKM2 (0.85/25)    32 dg  6 mag 12   42.3 h   103
IGAAN Igaz        Hodmezova.    HUHOD (0.8/3.8)   80 dg  3 mag 18   80.6 h   139
JOBKL Jobse       Oostkapelle   BETSY2 (1.2/85)   25 dg  7 mag 16   67.2 h   303
KACJA Kac         Kostanjevec   METKA (0.8/8)     42 dg  4 mag 15   42.2 h    55
                  Ljubljana     ORION1 (0.8/8)    42 dg  4 mag 21   73.2 h   110
                  Kamnik        REZIKA (0.8/6)    55 dg  3 mag 12   60.6 h   187
                                STEFKA (0.8/3.8)  80 dg  3 mag 11   33.0 h    42
LUNRO Lunsford    Chula Vista   BOCAM (1.4/50)    60 dg  6 mag  7   14.1 h   106
MOLSI Molau       Seysdorf      AVIS2 (1.4/50)    60 dg  6 mag 11   46.0 h   398
                                MINCAM1 (0.8/6)   55 dg  3 mag 20   56.6 h   105
                  Ketzuer       REMO1 (0.8/3.8)   80 dg  3 mag 25   90.8 h   136
                                REMO2 (0.8/3.8)   80 dg  3 mag 25  102.5 h   229
OCHPA Ochner      Albiano       ALBIANO (1.2/4.5) 68 dg  3 mag 24   80.2 h   141
PRZDA Przewozny   Berlin        ARMEFA (0.8/6)    55 dg  3 mag 10   42.7 h    84
SLAST Slavec      Ljubljana     KAYAK1 (1.8/28)   50 dg  4 mag 18   58.7 h    85
STOEN Stomeo      Scorze        MIN38 (0.8/3.8)   80 dg  3 mag 22  116.5 h   277
                                NOA38 (0.8/3.8)   80 dg  3 mag  8   36.3 h    48
                                SCO38 (0.8/3.8)   80 dg  3 mag 21  101.5 h   270
STRJO Strunk      Herford       MINCAM2 (0.8/6)   55 dg  3 mag 19   34.6 h    60
                                MINCAM3 (0.8/8)   42 dg  4 mag  7   12.3 h    24
                                MINCAM5 (0.8/6)   55 dg  3 mag 11   29.1 h    71
YRJIL Yrjola      Kuusankoski   FINEXCAM (0.8/6)  55 dg  3 mag  4   14.3 h    19
--------------------------------------------------------------------------------
Overall                                                        31 2006.6 h  4755


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

May    01   02   03   04   05   06   07   08   09   10   11   12   13   14   15
--------------------------------------------------------------------------------
BENOR   -   2.5   -    -    -    -    -    -    -    -    -    -    -    -    -
BRIBE  2.3  0.3  2.0  0.3   -   3.8  3.6  4.0  3.0   -   4.8   -    -    -   2.8
CASFL  3.0  5.6  2.2  3.0  1.0  2.9   -    -    -    -    -    -   1.0  0.5   -
       4.2  7.6  4.2  5.0  1.5  3.9   -    -    -    -    -    -   1.0   -   1.0
CRIST  7.8  4.8  6.7   -   7.1  6.6  3.1  2.6  7.1  7.4  4.1  3.0  7.3   -   1.0
ELTMA   -    -   5.4   -    -    -    -    -    -    -    -    -    -    -    -
GONRU  8.4  8.3  8.0  8.1  8.1  3.0  3.7  3.1   -    -    -    -    -   5.6  5.5
       8.4  6.3  3.2  6.2  6.1   -    -   3.9   -    -    -    -    -   6.0  1.5
GOVMI  5.5   -    -    -    -    -    -   5.7  6.6  7.5  4.6  0.6   -    -   4.3
HERCA  6.8  1.6  1.9  6.3  4.1  4.7  8.6  8.5  4.8  5.7  6.4  5.3  4.9  4.5  6.8
HINWO   -   0.7   -    -    -    -   5.0   -    -    -    -    -    -   2.0   -
IGAAN   -    -    -    -    -    -    -    -   6.5  5.3  8.3   -   1.0  1.7  5.0
JOBKL  6.2  3.1  4.6   -    -    -    -    -   2.8   -   5.6   -    -    -   5.3
KACJA  1.8   -   4.0   -   0.9   -   1.7  2.4  1.7  2.5  3.4   -    -    -    -
       3.9   -   1.5   -    -    -   3.4  1.4  1.3  2.3  5.2   -    -   0.4  3.1
        -    -   3.9   -   0.8   -   7.5  5.4  3.9   -   5.3   -    -    -    -
        -    -   1.2   -   1.6   -   7.5  2.4   -    -   4.4   -    -    -    -
LUNRO   -    -    -    -    -   2.0  1.9   -    -    -    -    -    -   2.3  3.0
MOLSI   -   4.3   -   4.2   -   0.6  5.7   -    -    -    -    -    -    -    -
       1.9  4.5   -   3.3   -   0.2  2.1  0.6  0.4  2.4   -    -    -    -    -
       6.8  4.7   -   6.5   -   6.4  4.3  2.2   -   1.1  3.1  6.0  5.9  5.8  0.3
       6.8  5.2  0.6  5.0   -   3.4  6.3  4.1   -   4.1  4.5  6.0  5.9  5.8  0.3
OCHPA  2.1  7.4  3.1  5.2  2.1  4.1  2.1  1.0   -   2.0  2.0  3.0  1.0   -    -
PRZDA   -   6.2   -    -    -   3.6  5.9   -    -    -   5.6   -   5.5   -    -
SLAST  2.5   -    -    -   1.0   -   2.5   -   3.3   -   2.0   -    -    -    -
STOEN  3.4  7.6  4.3   -   2.0   -   5.2  3.1  3.4   -   6.0   -   7.0   -    -
        -    -    -    -    -    -    -    -    -    -    -    -    -    -    -
       4.5  7.5  4.3   -   5.0   -   5.1  6.2  1.1   -   5.0   -   1.0   -    -
STRJO   -    -    -    -    -    -   2.1  2.5  0.7  1.0  3.9  4.5  0.5   -    -
        -    -    -    -    -    -    -   3.1   -    -    -   2.0  0.5   -    -
       2.0  2.7   -    -    -    -    -   3.3   -    -    -   3.5   -    -    -
YRJIL  3.8  3.9  3.9  2.7   -    -    -    -    -    -    -    -    -    -    -
--------------------------------------------------------------------------------
Sum   92.1 94.8 65.0 55.8 41.3 45.2 87.3 65.5 46.6 41.3 84.2 33.9 42.5 34.6 39.9

May    16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   31
-------------------------------------------------------------------------------------
BENOR   -    -    -    -   1.1  1.3   -    -    -    -    -    -    -    -    -    -
BRIBE  0.7  1.3  4.4  0.5  1.9  1.6  3.8  1.6  5.0  3.2  4.6   -   4.5  4.3  4.7  3.3
CASFL  2.8  1.8   -   1.7  1.0  2.5  3.8  2.0   -   1.0  1.4  5.4   -    -    -    -
       1.6  6.8  1.0  4.1  3.0  3.0   -   3.6  0.5  3.5  3.9  2.9   -    -    -    -
CRIST  5.0  5.9  6.0  6.0  6.0  5.9  2.0  6.8  4.6  5.6  5.1  5.5  5.8   -   3.0   -
ELTMA   -    -    -   1.9  2.2   -    -    -    -    -    -    -    -    -    -    -
GONRU   -   5.7  7.7  7.7  4.5  7.6   -    -    -   6.8  7.4  7.2  7.2  7.4  7.3  6.4
        -   4.7  4.7  4.7  2.5  5.6  1.5  1.7   -   2.9  5.5  5.3  4.3  5.4  6.3  3.5
GOVMI  6.0  7.2   -    -    -    -    -    -    -    -    -    -   1.3   -   3.1  6.7
HERCA  5.3   -   6.5   -    -    -    -   1.2  4.7  4.8  4.1  8.1  5.1  4.1  5.9  3.2
HINWO  5.9  0.7   -   2.0  5.5  0.8   -    -   5.5  5.4   -   4.0   -    -    -   4.8
IGAAN  6.0  2.0  2.5   -   5.5   -   2.0  5.3  6.0  5.5  3.8   -    -   5.0  2.7  6.5
JOBKL   -    -    -   5.0  2.5  4.8  1.8  4.5  4.5   -   4.5   -    -   4.1  3.6  4.3
KACJA  2.5  7.0  0.9   -   2.0  6.6  2.4   -   2.4   -    -    -    -    -    -    -
       7.0  5.0  6.9  3.7  3.9   -   6.8  2.7  1.0  3.6   -    -   4.0  1.6   -   4.5
        -    -    -    -   6.3  5.8  6.4  4.1  4.8   -    -    -    -    -    -   6.4
        -    -   2.3   -   2.6  4.8   -   0.1  1.6   -    -    -    -    -    -   4.5
LUNRO  2.5  1.0   -    -   1.4   -    -    -    -    -    -    -    -    -    -    -
MOLSI  5.8   -    -   5.1  5.4   -   5.0   -    -   5.1   -   2.6  2.2   -    -    -
       4.6   -   1.0  6.5  6.4   -   6.3   -   3.2  3.2   -   3.1  2.0  2.0  1.0  1.9
       0.7   -   3.6  1.5  1.6  1.4  5.3  1.3  3.2  4.1   -    -   5.0  4.4  3.8  1.8
       4.7   -   5.6  3.6  0.2  2.3  2.3   -   5.2  5.1   -    -   4.0  4.9  2.8  3.8
OCHPA   -   3.3  2.2  4.7  0.6   -   7.5   -   1.6  2.1   -   5.3  6.3  7.3  3.1  1.1
PRZDA  3.3   -    -    -    -   1.0   -   1.9  4.9  4.8   -    -    -    -    -    -
SLAST  1.5  2.8  6.2  6.5  4.6  1.8  2.9  3.4  5.2  3.7   -    -   2.1  2.6   -   4.1
STOEN  7.0  4.4  6.7  5.3  5.6  6.5  6.6  4.3   -   6.3   -   6.1  6.5  5.3  3.9   -
        -    -    -    -    -   1.8  6.6  3.5   -   3.8   -   6.1  6.4  6.3  1.8   -
       6.9  4.4  6.7  6.5  4.2  4.3   -   3.9   -   5.2   -   6.0  6.4  6.3  1.0   -
STRJO  1.5  0.7  0.9   -   1.0  1.7  2.2   -   3.4  1.2   -    -   2.3  2.0  1.5  1.0
        -    -    -    -    -    -    -    -   3.1   -    -    -   1.8  0.6  1.2   -
        -    -   1.0   -    -    -   3.0   -   4.2   -    -    -   3.1  2.8  1.3  2.2
YRJIL   -    -    -    -    -    -    -    -    -    -    -    -    -    -    -    -
-------------------------------------------------------------------------------------
Sum   81.3 64.7 76.8 77.0 81.5 71.1 78.2 51.9 74.6 86.9 40.3 67.6 80.3 76.4 58.0 70.0


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

May    01   02   03   04   05   06   07   08   09   10   11   12   13   14   15
--------------------------------------------------------------------------------
BENOR   -    2    -    -    -    -    -    -    -    -    -    -    -    -    -
BRIBE   4    1    9    1    -   13    8   10   10    -   10    -    -    -    6
CASFL   6   11    6    5    1   11    -    -    -    -    -    -    2    1    -
        6   11    5   11    1   11    -    -    -    -    -    -    1    -    1
CRIST  19   10    9    -   24   18    4   13   10   23    6    5   12    -    1
ELTMA   -    -    9    -    -    -    -    -    -    -    -    -    -    -    -
GONRU  19   19   26   28   24    5    8    7    -    -    -    -    -   25   15 
       14   16   10   27   21    -    -    8    -    -    -    -    -   12    2
GOVMI  19    -    -    -    -    -    -   13   18   16   12    1    -    -   11
HERCA  10    2    7    8    5    9    9   12   15    8   14    6   10    4    6
HINWO   -    4    -    -    -    -   15    -    -    -    -    -    -    5    -
IGAAN   -    -    -    -    -    -    -    -   17   13   16    -    2    2   13
JOBKL  24   12   19    -    -    -    -    -   11    -   20    -    -    -   22
KACJA   2    -    4    -    1    -    7    4    5    4    4    -    -    -    - 
        4    -    2    -    -    -   10    2    2    3    5    -    -    1    3 
        -    -   23    -    1    -   27   14   19    -   18    -    -    -    - 
        -    -    2    -    2    -    7    7    -    -    4    -    -    -    -
LUNRO   -    -    -    -    -   44   37    -    -    -    -    -    -    4   11
MOLSI   -   41    -   26    -    3   43    -    -    -    -    -    -    -    - 
        4    6    -    9    -    1    5    2    1    2    -    -    -    -    - 
       15    9    -    9    -    8    7    5    -    2    9    6   10    7    1 
       21    9    2   10    -    8    9    6    -    5   10   21   14   18    1
OCHPA   3   12    4   12    2   11    3    1    -    3    3    3    1    -    -
PRZDA   -   16    -    -    -    6   10    -    -    -   10    -    8    -    -
SLAST   2    -    -    -    1    -    2    -    6    -    2    -    -    -    -
STOEN  10   20   16    -    3    -   10    4    3    -   13    -    9    -    - 
        -    -    -    -    -    -    -    -    -    -    -    -    -    -    - 
        6   26   14    -    7    -   14   11    2    -    7    -    1    -    -
STRJO   -    -    -    -    -    -    3    7    4    1    5    6    1    -    - 
        -    -    -    -    -    -    -    5    -    -    -    4    1    -    - 
        3    4    -    -    -    -    -    8    -    -    -    7    -    -    -
YRJIL   7    5    3    4    -    -    -    -    -    -    -    -    -    -    -
--------------------------------------------------------------------------------
Sum   198  236  170  150   93  148  238  139  123   80  168   59   72   79   93

May    16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   31
-------------------------------------------------------------------------------------
BENOR   -    -    -    -    2    2    -    -    -    -    -    -    -    -    -    -
BRIBE   1    9   14    2    5    4   15    6   17    8   11    -   11   13   17    9
CASFL   3    3    -    4    2    3    9    3    -    2    2    8    -    -    -    - 
        3    6    2    9    3    4    -    4    1    5    6    6    -    -    -    -
CRIST  12   19   19   15   14   10    2   11   18   11   11   21   17    -    6    -
ELTMA   -    -    -    5    3    -    -    -    -    -    -    -    -    -    -    -
GONRU   -   24   21   15   16   12    -    -    -   19   19   27   25   21   23   16
        -   14   14    7    2   15    2    2    -    2   14    8   10    8   14    8
GOVMI  16   18    -    -    -    -    -    -    -    -    -    -    3    -    9   33
HERCA  10    -    8    -    -    -    -    2    4    4    6    9    7    7   10    3
HINWO  15    1    -    9   14    1    -    -   11   10    -   10    -    -    -    8
IGAAN   6    3    2    -    8    -    3    4   14   10    7    -    -    6    4    9
JOBKL   -    -    -   22    9   21   17   22   13    -   21    -    -   29   21   20
KACJA   5    6    1    -    2    6    2    -    2    -    -    -    -    -    -    - 
       12    4    8    4    4    -   13    5    1    4    -    -    5    5    -   13 
        -    -    -    -   19   11   12    6   14    -    -    -    -    -    -   23 
        -    -    2    -    7    4    -    1    2    -    -    -    -    -    -    4
LUNRO   5    3    -    -    2    -    -    -    -    -    -    -    -    -    -    -
MOLSI  61    -    -   50   41    -   50    -    -   36    -   17   30    -    -    -
       11    -    2    7   12    -   13    -    6    6    -    3    4    8    1    2 
        1    -    6    3    3    1    8    2    3    4    -    -    6    4    4    3 
        6    -   12    7    2    4    4    -   15   11    -    -   11   10    5    8
OCHPA   -    3    5    9    1    -   12    -    2    8    -    9    7   22    4    1
PRZDA   6    -    -    -    -    2    -    3   12   11    -    -    -    -    -    -
SLAST   2    4    8    9    7    3    8    4    6    3    -    -    3    5    -   10
STOEN  18    7   21   15   12    6   27    9    -   13    -   17   19   21    4    -
        -    -    -    -    -    2    7    3    -    3    -   12   11    8    2    -
       20    8   17   23   11    8    -    7    -   11    -   26   26   24    1    -
STRJO   2    1    2    -    2    2    4    -    7    3    -    -    2    5    2    1
        -    -    -    -    -    -    -    -    7    -    -    -    3    2    2    -
        -    -    1    -    -    -    6    -   12    -    -    -   10   13    2    5
YRJIL   -    -    -    -    -    -    -    -    -    -    -    -    -    -    -    -
-------------------------------------------------------------------------------------
Sum   215  133  165  215  203  121  214   94  167  184   97  173  210  211  131  176

Sirko Molau, 2009/06/25