Results of the IMO Video Meteor Network - July 2009
===================================================
July 2009 was an outstanding month, that raised the bar of the camera network
still a bit higher. Let's start with our new observer Istvan Tepliczky, who
is the second Hungarian supporting the video network. His camera HUMOB has
not yet found a fixed observing site and was therefor operated at different
locations in July. Together with Istvan, we had 20 observers operating
34 cameras all together in July.
Next the weather should be mentioned, which was unusually good. In particular
our observers in southern Europe rarely suffered from clouded nights and,
thus, a total of 16 cameras obtained 20 or more observing nights. In the last
week of July, there was fine weather at almost every observing site with
close to 30 cameras active each night. Even though July is the month with the
second shortest nights in the northern hemisphere, we managed to obtain more
than 2,700 hours of effective observing time. That's not only the by far best
July result to date, but the second best monthly result in the full history
of the video network! Whereas the meteor counts remained low in the first
few days of July, there was a significant increase once the moon disappeared
in the middle of the month. Just as you get in mid-January the impression,
that meteor counts are cut half from one day to the next, it felt as if they
were doubling after mid-July. Beside the moon, the slowly raising Perseid
activity and the maximum of the southern delta-Aquariids were to blame for
this effect. On July 29, we recorded again more than 1,000 meteors in a
single night, and by the end of July more than 13,000 meteors in total were
obtained by the observers.
Once more, there were also outstanding events in the previous month. Enrico
Stomeo managed to record two blazing fireballs of visually estimated -11 mag
(recorded by MIN38 and NOA38) and -20 mag (recorded by MIN38, NOA38 and SCO38)
within two nights (figure 1). Such meteors are ways too bright for our cameras
with are tuned for sensitivity, which is why they are hard to analyse. Still,
at least a few points along their trajectory could be measured in both cases.
Figure 1: Two bright fireballs recorded by Enrico Stomeo. On top an ANT from
July 17, 2009, 00:46 UT, and on bottom an SDA from July 19, 2009, 01:59 UT.
Now let's have a closer look at the southern delta-Aquariids, the dominating
shower of the month. In our video database, they can be tracked from July 21
until well into September. However, the last radiant positions are quite
uncertain, which is why we defined the end date as August 23 (figure 2).
Figure 2: Radiant position of the southern delta-Aquariids from data of the
IMO Video Meteor Database.
The long term analysis of all data until 2008 shows a plateau of almost
constant activity at maximum between July 27 and 31 reaching a video rate
(comparable to the visual ZHR) of about 18. The highest value occurs on
July 30 (solar longitude 127 deg), thereafter the activity drops clearly but
can be detected at a low level for a long time (figure 3, red bars). For the
analysis of the 2009 data, the number of SDA (1325 in total) was divided by
the number of sporadics (4564 in total) to get an estimate of the shower
activity for each night (figure 3, green line). Both graphs match well, but
highest SDA activity in this years occurred already at the night of July
28/29.
Figure 3: Long-term activity profile of the southern delta-Aquariids
(red bars). The green line represents the ratio between SDA and SPO in
July 2009.
During the latest analysis of the southern delta-Aquariids we noted, that
the velocity of this shower was not constant but decreased slowly. I had
observed this effect already during earlier analyses of long-lasting meteor
showers, but thought that to be systematic errors of our analysis method.
This time we asked the network coordinator of the Japanese SonotaCo network,
and to my surprise SonotaCo observed the same trend towards lower velocities
in his SDA orbits obtained from double station data (figure 4). Even though
the decrease is smaller than in the IMO data, the tendency is unequivocal.
The same consensus was obtained for three other showers that we compared.
So now we believe that this effect, for which we have first ideas but no
consistent explanation yet, is real.
Figure 4: Meteor shower velocity v_inf of the southern delta-Aquariids and
the alpha-Capricornids over solar longitude.
By the end of July, the alpha-Capricornids reach their activity maximum
as well, but their peak video rate of 5 is significantly lower. Also this
shower has a plateau of almost constant maximum activity between July 23
and 28, with the largest value at the end of the period (solar longitude
125 deg). The radiant position is well defined between July 11 and
August 11 (figure 5).
Figure 5: Radiant position of the alpha-Capricornids from data of the
IMO Video Meteor Database.
The ratio between alpha-Capricornids (900 in total) and sporadics (8420
in total) confirms the late maximum on July 29 (figure 6). Hence, there
were two active southern showers in these nights, which is well reflected
in the radiant plots of some cameras. Figure 7 shows a section from the
corresponding plot of MIN38 on July 28/29.
Figure 6: Long-term activity profile of the alpha-Capricornids (red bars).
The green line shows the ratio between CAP and SPO in July 2009.
Figure 7: The radiant plot of MIN38 from July 28/29 shows the southern
delta-Aquariids radiant left and the alpha-Capricornids radiant right.
Last but not least it should be mentioned, that we observed a decreasing
velocity for the alpha-Capricornids as well. With -0.18 km/s per degree
solar longitude, the value was slightly smaller than for the southern
delta-Aquariids (figure 4).
1. Observers
============
Code Name Place Camera FOV LM Nights Time Meteors
--------------------------------------------------------------------------------
BRIBE Brinkmann Herne HERMINE (0.8/6) 55 dg 3 mag 23 69.6 h 309
CASFL Castellani Monte Baldo BMH1 (0.8/6) 55 dg 3 mag 8 36.4 h 136
BMH2 (0.8/6) 55 dg 3 mag 9 47.8 h 218
CRIST Crivello Valbrevenna C3P8 (0.8/3.8) 80 dg 3 mag 27 138.9 h 750
STG38 (0.8/3.8) 80 dg 3 mag 10 54.4 h 224
ELTMA Eltri Venezia MET38 (0.8/3.8) 80 dg 3 mag 17 93.5 h 349
GONRU Goncalves Tomar TEMPLAR1 (0.8/6) 55 dg 3 mag 28 181.0 h 1075
TEMPLAR2 (0.8/6) 55 dg 3 mag 28 155.7 h 585
GOVMI Govedic Sredisce ORION2 (0.8/8) 42 dg 4 mag 28 139.7 h 946
HERCA Hergenroth. Tucson SALSA (1.2/4) 80 dg 3 mag 23 75.1 h 148
SALSA2 (1.2/4) 80 dg 3 mag 23 86.7 h 225
HINWO Hinz Brannenburg AKM2 (0.85/25) 32 dg 6 mag 16 66.5 h 365
IGAAN Igaz Hodmezova. HUHOD (0.8/3.8) 80 dg 3 mag 12 85.2 h 434
JOBKL Jobse Oostkapelle BETSY2 (1.2/85) 25 dg 7 mag 13 55.8 h 335
KACJA Kac Kostanjevec METKA (0.8/8) 42 dg 4 mag 18 84.9 h 185
Ljubljana ORION1 (0.8/8) 42 dg 4 mag 27 112.2 h 310
Kamnik REZIKA (0.8/6) 55 dg 3 mag 11 42.1 h 265
STEFKA (0.8/3.8) 80 dg 3 mag 7 25.7 h 63
KOSDE Koschny Noordwijkerh. TEC1 (1.4/12) 30 dg 4 mag 17 40.2 h 95
LUNRO Lunsford Chula Vista BOCAM (1.4/50) 60 dg 6 mag 25 118.5 h 641
MOLSI Molau Seysdorf AVIS2 (1.4/50) 60 dg 6 mag 20 67.6 h 1032
MINCAM1 (0.8/6) 55 dg 3 mag 26 96.9 h 405
Ketzuer REMO1 (0.8/3.8) 80 dg 3 mag 23 80.8 h 203
REMO2 (0.8/3.8) 80 dg 3 mag 26 90.3 h 445
OCHPA Ochner Albiano ALBIANO (1.2/4.5) 68 dg 3 mag 17 74.1 h 171
SLAST Slavec Ljubljana KAYAK1 (1.8/28) 50 dg 4 mag 18 43.9 h 86
STOEN Stomeo Scorze MIN38 (0.8/3.8) 80 dg 3 mag 27 139.8 h 1047
NOA38 (0.8/3.8) 80 dg 3 mag 26 125.6 h 545
SCO38 (0.8/3.8) 80 dg 3 mag 27 142.9 h 896
STORO Stork Ondrejov OND1 (1.5/50) 55 dg 6 mag 2 9.4 h 232
STRJO Strunk Herford MINCAM2 (0.8/6) 55 dg 3 mag 14 37.5 h 115
MINCAM3 (0.8/8) 42 dg 4 mag 8 20.1 h 71
MINCAM5 (0.8/6) 55 dg 3 mag 12 35.0 h 185
TEPIS Tepliczky Budapest HUMOB (0.8/3.8) 80 dg 3 mag 6 33.6 h 295
--------------------------------------------------------------------------------
Overall 31 2707.4 h 13485
2. Observing Times (h)
======================
July 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
--------------------------------------------------------------------------------
BRIBE 3.4 5.9 0.8 4.3 - 2.3 - 0.3 0.3 - - 4.7 2.4 2.8 4.4
CASFL - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - -
CRIST 2.0 4.3 3.7 - - 2.4 3.2 4.3 3.7 6.5 3.5 2.0 5.6 6.5 6.6
- - - 1.0 - - - - - - 4.3 - - - -
ELTMA - - - - - - - - - - - 4.4 - 4.3 -
GONRU 2.7 7.1 6.1 7.0 5.4 6.1 7.0 7.3 3.8 2.3 6.2 - 7.3 7.3 7.3
1.1 7.1 7.1 1.9 3.4 4.0 3.9 7.2 1.9 1.3 6.2 - 7.3 7.3 7.3
GOVMI 3.7 3.5 1.2 3.1 6.5 2.5 3.4 4.1 1.9 3.2 5.6 4.4 - 6.8 3.4
HERCA - - 2.4 - 5.4 2.9 - 2.1 0.9 1.0 4.5 3.7 1.2 1.5 -
- - - - 5.4 2.9 - 2.1 2.9 1.0 4.5 4.7 4.2 5.5 -
HINWO 3.1 0.5 - 1.4 - - - - - - 3.5 - 4.5 4.3 4.1
IGAAN - - - - - - - - - - - - - - -
JOBKL 3.8 - 4.1 4.1 - 2.2 - 4.5 - - - 5.8 - 4.7 5.3
KACJA - - - 2.5 2.5 - - 1.0 - - 2.1 2.6 6.1 4.8 -
1.0 4.3 - 4.4 - 1.0 - 0.6 - 1.2 5.0 4.5 4.5 4.6 3.6
- 5.3 - - 3.4 - - 1.7 1.0 - - 3.3 2.0 - 3.3
- 4.6 - - 2.4 - - - - - - 2.3 - - -
KOSDE - 2.7 - 2.8 2.5 - - - - - - 2.2 3.6 1.3 4.0
LUNRO - 2.1 1.0 1.9 3.5 2.6 2.7 2.2 1.4 2.6 2.9 7.4 7.7 5.8 7.8
MOLSI 2.3 3.3 - 1.3 - - - 0.1 - - 1.1 - 2.2 1.4 5.4
5.6 1.6 - 3.7 3.7 0.9 1.0 1.8 - 2.9 3.4 - 3.9 1.9 1.1
2.4 4.4 1.5 2.5 4.5 1.7 - - - 1.2 4.8 - 3.8 3.9 3.0
4.4 4.5 2.9 1.0 4.5 1.0 - - - 1.2 4.8 0.4 4.9 5.0 2.5
OCHPA - - - - - - - - - - - - 2.1 5.2 7.3
SLAST 1.2 3.5 - 2.0 2.1 - - 1.5 - - 1.1 4.2 - 5.1 3.2
STOEN 5.0 3.5 2.2 - 3.9 - - 5.2 4.1 4.5 4.1 5.3 3.2 6.5 6.4
3.5 3.0 3.0 - 2.7 - - 4.2 3.1 4.5 5.2 6.3 2.2 5.4 6.4
4.0 4.0 2.7 - 2.3 - - 6.1 3.2 4.4 5.1 6.3 3.3 5.4 6.4
STORO - - - - - - - - - - - - - - -
STRJO 2.4 1.9 - 3.0 - - - - 3.1 - - - 1.7 - 3.2
- - - - - - 2.7 - - - - - - - 1.0
- - - - - - 1.0 - - - - - 3.1 2.0 2.0
TEPIS - - - - - - - - - - - - - - -
--------------------------------------------------------------------------------
Sum 51.6 77.1 38.7 47.9 64.1 32.5 24.9 56.3 31.3 37.8 77.9 74.5 86.8109.3105.0
July 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
-------------------------------------------------------------------------------------
BRIBE 3.6 - 3.3 0.6 - 0.4 - - 0.4 5.6 3.1 5.1 5.3 1.1 4.6 4.9
CASFL - - - - - - - - 3.3 2.8 6.8 3.9 4.4 6.0 4.5 4.7
- - - - - 4.5 6.7 4.7 5.1 2.5 6.2 4.2 6.9 7.0 - -
CRIST 6.7 - 5.6 3.5 2.3 6.9 6.9 4.9 - 7.0 7.1 7.1 7.2 7.2 7.2 5.0
- - 5.6 6.8 6.8 4.7 5.9 6.9 6.0 6.4 - - - - - -
ELTMA 5.4 - 5.0 6.8 4.4 6.8 4.9 5.7 5.3 3.4 7.0 6.8 5.8 6.9 4.5 6.1
GONRU 7.3 7.4 7.5 5.5 - 4.2 - 7.6 7.5 7.7 7.7 7.7 7.8 7.8 7.3 5.1
7.4 7.4 7.5 4.0 - 4.2 - 6.6 6.0 7.7 5.7 7.7 6.3 5.8 6.8 5.6
GOVMI 6.8 6.5 6.5 6.5 7.0 7.0 7.1 7.1 - 5.9 6.5 6.1 4.6 7.0 - 1.8
HERCA 2.9 - 2.0 1.1 - 1.6 - 0.5 0.5 1.0 2.1 8.4 8.4 7.8 6.4 6.8
0.9 - 3.0 1.1 1.1 1.6 3.4 - 0.5 1.0 3.1 8.4 8.4 7.8 6.4 6.8
HINWO 5.4 - - 1.3 5.6 5.7 5.4 - - - 5.2 - 6.0 5.5 - 5.0
IGAAN - - - - 7.2 7.2 7.3 6.8 7.3 7.4 7.4 7.4 7.5 7.0 7.1 5.6
JOBKL - - - - - - - 4.5 - 5.3 - 4.4 - - 5.6 1.5
KACJA 6.8 - - 5.8 4.8 6.9 3.9 4.1 - 5.6 7.2 7.3 - 7.3 - 3.6
6.7 4.6 2.7 6.7 4.3 3.9 4.4 5.9 0.8 7.0 6.5 7.2 4.2 6.7 2.5 3.4
3.8 - - - - 6.7 6.8 - - 4.8 - - - - - -
3.9 - - - - 1.8 5.9 - - 4.8 - - - - - -
KOSDE 0.6 0.9 - - 2.0 1.2 - 2.7 2.4 1.8 - 4.1 - - 1.8 3.6
LUNRO 7.3 6.7 4.9 6.4 7.8 7.6 8.0 4.4 - 6.0 - - - - 3.9 3.9
MOLSI 3.6 - - 4.0 4.4 5.0 1.2 - - 5.0 5.5 1.4 5.7 5.6 3.6 5.5
6.2 - - 5.3 5.8 5.4 1.5 4.0 1.0 6.6 6.6 1.8 6.7 6.8 1.8 5.9
5.1 - - 4.3 2.3 - 3.0 3.5 5.6 4.2 1.2 - 5.9 4.4 1.5 6.1
5.1 - - 0.3 3.9 0.3 5.5 4.5 4.1 5.6 3.2 1.3 5.9 5.9 1.5 6.1
OCHPA 6.3 - 2.1 4.3 3.2 2.2 4.3 6.5 - 6.6 2.2 5.6 2.2 5.6 3.4 5.0
SLAST 6.1 0.7 - - - - - - - 0.8 1.8 1.3 4.3 0.7 1.9 2.4
STOEN 5.4 1.0 6.5 6.6 6.6 4.0 6.6 6.6 5.9 - 6.9 6.9 7.0 6.8 4.7 4.4
4.3 - 6.5 5.5 4.5 3.0 6.6 5.5 3.7 - 6.9 6.9 7.0 6.8 5.0 3.9
6.5 1.4 6.5 6.5 6.7 4.5 6.5 6.6 4.3 - 6.9 6.9 7.0 6.8 5.7 6.9
STORO - - - - - - - - - - - - - 4.3 5.1 -
STRJO 4.5 - 3.6 0.5 1.0 - - - - 1.6 - - 5.2 - 0.3 5.5
1.7 - 0.7 - - - - - - 0.7 - - 5.2 - 2.7 5.4
4.2 - 2.9 1.7 - - - - - 3.1 0.7 - 5.3 - 3.6 5.4
TEPIS - - - - - - - - - 5.2 5.9 5.3 5.2 6.1 5.9 -
-------------------------------------------------------------------------------------
Sum 134.5 36.6 82.4 95.1 91.7107.3111.8109.6 69.7133.1129.4133.2155.4150.7115.3135.9
3. Results (Meteors)
====================
July 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
--------------------------------------------------------------------------------
BRIBE 11 7 3 15 - 6 - 1 2 - - 14 9 9 27
CASFL - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - -
CRIST 2 24 14 - - 4 6 16 13 16 10 10 19 26 45
- - - 1 - - - - - - 18 - - - -
ELTMA - - - - - - - - - - - 12 - 5 -
GONRU 12 29 39 21 33 23 35 27 12 7 36 - 33 53 47
2 27 21 8 9 7 13 17 3 3 21 - 21 40 29
GOVMI 10 15 5 17 27 24 13 21 2 13 16 15 - 27 14
HERCA - - 2 - 7 7 - 2 2 3 8 4 2 2 -
- - - - 8 4 - 3 5 1 4 11 5 5 -
HINWO 16 1 - 4 - - - - - - 20 - 12 13 16
IGAAN - - - - - - - - - - - - - - -
JOBKL 15 - 18 18 - 7 - 14 - - - 35 - 17 37
KACJA - - - 6 6 - - 1 - - 2 7 10 7 -
1 6 - 7 - 1 - 1 - 1 9 8 11 11 5
- 29 - - 24 - - 2 2 - - 15 7 - 21
- 10 - - 5 - - - - - - 7 - - -
KOSDE - 5 - 6 5 - - - - - - 7 8 4 9
LUNRO - 3 3 5 7 4 3 3 2 4 7 32 40 19 39
MOLSI 35 20 - 4 - - - 1 - - 4 - 20 10 40
10 4 - 5 8 1 2 3 - 12 18 - 9 3 2
5 8 3 5 15 7 - - - 3 11 - 16 14 6
10 16 7 4 17 5 - - - 4 13 1 28 20 10
OCHPA - - - - - - - - - - - - 3 16 14
SLAST 2 8 - 3 3 - - 2 - - 2 9 - 9 3
STOEN 22 18 4 - 19 - - 20 7 31 21 35 9 34 37
7 6 5 - 5 - - 10 3 15 15 24 4 18 22
14 15 6 - 6 - - 24 9 43 22 41 11 18 35
STORO - - - - - - - - - - - - - - -
STRJO 3 3 - 4 - - - - 8 - - - 5 - 12
- - - - - - 6 - - - - - - - 5
- - - - - - 5 - - - - - 6 5 12
TEPIS - - - - - - - - - - - - - - -
-------------------------------------------------------------------------------
Sum 177 254 130 133 204 100 83 168 70 156 257 287 288 385 487
July 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
-------------------------------------------------------------------------------------
BRIBE 8 - 12 3 - 2 - - 3 24 14 34 20 5 40 40
CASFL - - - - - - - - 18 11 21 13 14 25 15 19
- - - - - 12 23 19 25 10 33 18 29 49 - -
CRIST 25 - 36 15 19 18 23 20 - 42 67 70 73 54 44 39
- - 36 31 25 14 15 37 18 29 - - - - - -
ELTMA 17 - 15 16 10 12 17 17 18 8 39 36 33 42 30 22
GONRU 46 34 36 20 - 25 - 44 52 56 50 76 62 75 51 41
19 29 21 10 - 10 - 24 28 37 23 45 33 35 32 18
GOVMI 40 23 29 57 40 47 34 44 - 80 96 83 83 60 - 11
HERCA 3 - 2 3 - 2 - 1 1 1 5 12 12 28 16 23
1 - 3 3 4 3 7 - 1 2 11 35 21 29 23 36
HINWO 15 - - 3 29 29 33 - - - 42 - 51 47 - 34
IGAAN - - - - 25 45 32 25 32 30 50 41 52 34 45 23
JOBKL - - - - - - - 28 - 51 - 32 - - 52 11
KACJA 13 - - 8 9 14 7 10 - 12 16 30 - 19 - 8
20 9 4 20 12 13 9 17 1 23 21 29 31 19 3 18
32 - - - - 39 35 - - 59 - - - - - -
8 - - - - 4 10 - - 19 - - - - - -
KOSDE 1 3 - - 2 3 - 4 6 6 - 12 - - 5 9
LUNRO 30 41 16 17 37 37 30 12 - 21 - - - - 129 100
MOLSI 59 - - 67 69 86 11 - - 85 136 4 114 119 31 117
22 - - 18 20 19 3 31 5 38 45 3 42 43 5 34
21 - - 8 6 - 5 7 23 19 14 - 43 13 4 46
34 - - 1 14 4 23 13 18 26 12 4 50 38 8 65
OCHPA 11 - 7 8 6 3 13 12 - 11 3 13 7 16 14 14
SLAST 13 2 - - - - - - - 2 5 2 14 1 3 3
STOEN 48 1 45 46 46 30 34 53 49 - 83 78 81 94 56 46
21 - 30 24 16 15 19 28 24 - 46 42 45 44 38 19
31 3 56 55 33 32 23 48 37 - 68 61 47 77 38 43
STORO - - - - - - - - - - - - - 149 83 -
STRJO 10 - 9 1 2 - - - - 8 - - 21 - 1 28
4 - 1 - - - - - - 1 - - 21 - 14 19
20 - 12 5 - - - - - 14 4 - 29 - 27 46
TEPIS - - - - - - - - - 53 51 61 31 46 53 -
------------------------------------------------------------------------------------
Sum 572 145 370 439 424 518 406 494 359 778 955 834 1059 1161 860 932
Sirko Molau, 2009/09/04