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