Results of the IMO Video Meteor Network - April 2009
====================================================
In the previous month, also the more northern observers were finally rewarded
with fine observing conditions again. Most cameras could obtain long observing
series with only a few days missing. Almost all German observers managed to
collect more than 20 observing nights, whereas in Southern Europe the weather
was less optimal this time.
With more than 2,100 hours of effective observing time and 5,000 meteors, we
achieved once more a new April record. However, that was not only thanks to
the fine weather, but also a result of 34 cameras that were operated, which
marks another record. Enrico Stomeo, for example, installed the new camera
MIN26. Utilizing the Computar 2.6mm lens (f/1.0), this is now the camera with
the single largest field of view (140 degrees diagonally). The biggest
challenge was to measure the reference stars such, that there are no major
position errors despite the image distortion. After a few fruitless trials
it could be shown, that the third order plate constants used by MetRec are
indeed able to describe such strong distortion sufficiently if only enough
reference stars (>80) distributed over the full field of view are measured.
Enrico benefited from a new function in RefStars, which allows to measure
several (at different times recorded) reference images together in order to
get more reference stars. It is even possible to measure the same stars at
different times again - the only requirement is that the full field of view
is completely covered by measuring points.
We could also welcome two new observers in April: Mitja Govedic from Slovenia
has taken over ORION2 from Javor Kac and provided first observations to the
camera network. With Antal Igaz, we now also have a Hungarian observer on
board. After a longer preparation phase, Antal is operating the two automatic
stations HUBUD and HUHOD with Watec cameras and Computar 3.8mm lenses. It's
the begin of a small camera network, that shall finally cover the full night
sky over Hungary with double station observations.
With respect to meteor showers, the Lyrids are the only rays of hope in the
annual spring minimum. This year, their maximum was predicted for mid-day (UT)
of April 22. So most European observers could only witness the ascending and
the descending activity branch, which is why the total number of Lyrids was
not so impressive. Only Bob Lunsford was able to capture the maximum well
under dark desert skies at the American west coast. He recorded a total of
29 Lyrids, whereby their hourly number was nearly constant between 9 and 12 UT.
Based on a total of 1,500 Lyrids, the 2008 analysis of the video meteor
database yielded an interval of activity between April 19 and 25, which falls
somewhat short of the value given in the IMO meteor shower list (April 16-25).
The absolute position of the video radiant matches well to the value from
literature, but the direction of the radiant drift is slightly different
(figure 1). The Lyrids velocity was determined to 46 km/s, which is notably
smaller than the value given in the IMO handbook (49 km/s), but matches well
to the figure given by IAU (47.1 km/s).
Figure 1: Radiant position of the Lyrids from data of the IMO Video Meteor
Database.
According to the video data, the Lyrids reach their peak activity on April
22/23 at about 32.5° solar longitude. The peak rate lies between 10 and 15
per hour - two days before and after the maximum is has dropped already
below two, though (figure 2). According to the IMO handbook, the maximum
obtained from visual data occurs at 32.3°, which confirms the video result
nicely. Only the ascending activity branch shows a larger deviation. Similar
to the Quadrantids, the visual ZHR is here clearly above the video rate.
Maybe the observers are too exited when they await the only larger shower
in spring, so that they become somewhat generous in the meteor shower
assignment?
Figure 2: Long-term activity profile of the Lyrids. The blue dots present
the ZHR profile obtained from visual data.
1. Observers
============
Code Name Place Camera FOV LM Nights Time Meteors
--------------------------------------------------------------------------------
BRIBE Brinkmann Herne HERMINE (0.8/6) 55 dg 3 mag 22 88.0 h 205
CASFL Castellani Monte Baldo BMH1 (0.8/6) 55 dg 3 mag 15 51.5 h 66
BMH2 (0.8/6) 55 dg 3 mag 13 57.7 h 85
CRIST Crivello Genova C3P8 (0.8/3.8) 80 dg 3 mag 18 79.2 h 189
GONRU Goncalves Tomar TEMPLAR1 (0.8/6) 55 dg 3 mag 12 75.8 h 225
TEMPLAR2 (0.8/6) 55 dg 3 mag 13 70.4 h 154
GOVMI Govedic Sredisce ORION2 (0.8/8) 42 dg 4 mag 2 10.2 h 42
HERCA Hergenroth. Tucson SALSA (1.2/4) 80 dg 3 mag 26 135.8 h 192
HINWO Hinz Brannenburg AKM2 (0.85/25) 32 dg 6 mag 17 84.3 h 165
IGAAN Antal Budapest HUBUD (0.8/3.8) 80 dg 3 mag 6 36.3 h 72
Hodmezova. HUHOD (0.8/3.8) 80 dg 3 mag 7 35.9 h 54
JOBKL Jobse Oostkapelle BETSY2 (1.2/85) 25 dg 7 mag 4 24.2 h 116
KACJA Kac Kostanjevec METKA (0.8/8) 42 dg 4 mag 14 62.7 h 72
Ljubljana ORION1 (0.8/8) 42 dg 4 mag 15 52.4 h 70
Kamnik REZIKA (0.8/6) 55 dg 3 mag 14 95.4 h 247
STEFKA (0.8/3.8) 80 dg 3 mag 5 13.8 h 22
LUNRO Lunsford Chula Vista BOCAM (1.4/50) 60 dg 6 mag 11 57.2 h 245
MOLSI Molau Seysdorf AVIS2 (1.4/50) 60 dg 6 mag 12 72.0 h 656
MINCAM1 (0.8/6) 55 dg 3 mag 23 96.3 h 171
Ketzuer REMO1 (0.8/3.8) 80 dg 3 mag 15 84.7 h 114
REMO2 (0.8/3.8) 80 dg 3 mag 15 90.1 h 189
OCHPA Ochner Albiano ALBIANO (1.2/4.5) 68 dg 3 mag 19 53.9 h 85
PRZDA Przewozny Berlin ARMEFA (0.8/6) 55 dg 3 mag 22 145.0 h 287
SLAST Slavec Ljubljana KAYAK1 (1.8/28) 50 dg 4 mag 8 24.6 h 34
STOEN Stomeo Scorze MIN26 (1.0/2.6) 120 dg 2 mag 11 43.4 h 61
MIN38 (0.8/3.8) 80 dg 3 mag 17 99.7 h 255
SCO38 (0.8/3.8) 80 dg 3 mag 18 90.7 h 308
STORO Stork Kunzak KUN1 (1.4/50) 55 dg 6 mag 2 13.3 h 195
Ondrejov OND1 (1.4/50) 55 dg 6 mag 2 13.6 h 173
STRJO Strunk Herford MINCAM2 (0.8/6) 55 dg 3 mag 20 58.1 h 82
MINCAM3 (0.8/8) 42 dg 4 mag 11 28.3 h 42
MINCAM5 (0.8/6) 55 dg 3 mag 21 81.6 h 166
YRJIL Yrjola Kuusankoski FINEXCAM (0.8/6) 55 dg 3 mag 19 81.7 h 162
--------------------------------------------------------------------------------
Overall 30 2144.2 h 5243
2. Observing Times (h)
======================
Apr 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
--------------------------------------------------------------------------------
BRIBE 5.5 8.7 0.3 - - 4.2 0.7 - 8.3 7.9 0.5 - 0.5 5.9 5.6
CASFL - 1.5 - - - - 5.8 2.3 3.8 6.4 1.0 8.8 2.0 4.1 2.3
- 2.6 - - - - 4.8 1.3 6.9 2.2 - 8.8 2.7 6.6 3.1
CRIST - 5.7 8.4 - 7.0 - 5.0 6.0 1.0 - - 4.8 2.0 2.9 2.7
GONRU - - - - - 1.2 - 9.2 - 1.1 2.1 9.1 - - -
- - - - - 2.8 6.6 6.2 - 1.8 4.9 7.1 - - -
GOVMI - - - - - - - - - - - - - - -
HERCA 9.7 4.0 2.8 1.3 3.9 2.3 7.0 2.2 0.9 - - - 1.8 1.3 -
HINWO - - - - - 1.3 0.5 - 1.7 6.0 4.2 8.1 6.0 5.1 4.9
IGAAN - - - - - - - - - - - - - - -
- - - - - - 3.8 - - - - 8.2 - 5.8 8.8
JOBKL - - - - - - - - - - - - - - -
KACJA - - - 4.4 - - - 4.7 3.9 3.0 5.0 4.1 4.4 6.9 1.8
- - - 1.6 1.5 5.9 4.9 2.0 3.7 4.8 3.7 1.8 4.6 - 3.6
- - - 9.4 8.3 5.2 7.5 6.2 5.4 4.4 9.0 8.5 8.8 6.7 5.7
- - - - - - 3.2 2.2 0.3 - - - - - -
KOSDE - - - - - 1.5 - 7.1 2.8 - - - - - -
LUNRO 3.3 - - - 8.5 5.7 9.4 - - - - - 2.2 - -
MOLSI - 8.8 6.9 - - 5.4 4.8 - - - - - - - -
- 4.3 3.3 2.2 - 3.2 2.0 2.0 4.9 3.8 3.8 5.7 1.6 8.6 2.5
6.1 9.0 3.4 - 1.3 0.7 5.4 1.7 4.3 8.3 8.3 8.1 8.1 8.1 8.0
1.6 9.0 9.0 - 3.3 2.7 3.6 1.5 6.5 8.4 8.3 8.1 8.1 8.1 8.0
OCHPA - - 5.4 - 3.2 7.4 - 1.0 1.0 4.2 1.0 4.1 3.3 2.1 1.1
PRZDA 7.6 8.3 5.3 - 4.1 5.1 4.0 6.8 - 7.8 7.7 7.6 7.6 7.5 7.4
SLAST - - - - - - 1.4 - 1.0 3.0 - - - 1.3 4.7
STOEN - - - - 4.1 - 2.9 - - 5.2 2.0 7.5 4.9 4.5 2.7
2.1 5.1 - - 6.4 - 7.0 - - 8.6 3.1 8.6 6.9 8.4 6.4
2.2 3.0 - - 6.2 - 8.0 - 0.9 8.5 2.1 6.4 5.8 7.2 7.5
STORO - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - -
STRJO 5.8 6.6 1.7 - - 1.0 - 1.4 4.5 1.4 2.9 3.7 1.0 6.7 5.0
3.1 2.4 3.9 - - 1.0 - - 3.2 5.2 2.4 - - 1.5 1.5
7.3 4.8 4.3 - - 2.2 - - 6.2 1.7 5.0 5.6 5.5 6.2 2.2
YRJIL 7.7 - - - - - - 2.9 2.9 3.8 - - - 4.8 6.3
--------------------------------------------------------------------------------
Sum 62.0 83.8 54.7 18.9 57.8 58.8 98.3 66.7 74.1107.5 77.0134.7 87.8120.3101.8
Apr 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
--------------------------------------------------------------------------------
BRIBE - 1.2 1.7 6.9 8.6 8.5 - 6.6 2.4 0.3 - - 0.6 1.4 1.7
CASFL - - - - - 1.4 1.5 - 6.1 0.5 - - - - 4.0
- - - - - 5.7 1.7 - 6.1 - - - - - 5.2
CRIST 1.9 2.0 - - - 4.4 8.3 - - 1.0 - - 5.3 3.0 7.8
GONRU 1.6 - - - 8.7 8.7 8.7 8.6 - - 8.4 - - - 8.4
0.8 - - - 6.8 5.8 7.7 7.1 - - 6.4 - - - 6.4
GOVMI - - - - - - - - 4.8 5.4 - - - - -
HERCA 5.2 4.8 4.1 6.3 7.8 6.7 8.7 9.2 6.7 5.2 2.5 7.9 6.9 7.8 8.8
HINWO - 5.3 6.1 - 5.4 6.5 - 5.6 7.4 5.2 5.0 - - - -
IGAAN - - - - - 8.0 - 5.6 - 7.1 5.9 5.0 - 4.7 -
3.7 4.8 0.8 - - - - - - - - - - - -
JOBKL - - - - - - - - 5.6 - - - 6.2 6.3 6.1
KACJA - 7.6 1.6 - - 6.6 - - 4.2 4.5 - - - - -
- 1.8 - - - 6.3 3.1 - - 3.1 - - - - -
- - - - - - 6.7 - - 3.6 - - - - -
- - - - - - 4.9 - - 3.2 - - - - -
KOSDE - - 0.6 3.5 1.1 4.3 7.7 4.3 3.5 - - - - - -
LUNRO - 1.6 8.5 8.8 3.1 2.0 4.1 - - - - - - - -
MOLSI - - - 5.9 7.3 6.3 5.8 3.8 6.8 6.0 4.2 - - - -
- - 4.3 5.2 8.2 8.1 6.1 2.9 7.9 2.5 2.8 - - - 0.4
3.9 - - - - - - - - - - - - - -
3.9 - - - - - - - - - - - - - -
OCHPA - 2.1 - 1.0 5.0 2.0 2.0 5.9 1.1 - - - - 1.0 -
PRZDA - - 7.2 7.1 7.1 7.0 2.9 6.8 6.8 6.7 6.6 - - - -
SLAST - - 4.3 - - - 4.1 - - 4.8 - - - - -
STOEN - 3.9 - - - - 2.2 3.5 - - - - - - -
- 8.0 3.7 - - 6.0 6.1 4.6 - 3.2 - - - - 5.5
- 7.1 3.1 - - 7.0 5.0 3.5 - 2.1 - - - - 5.1
STORO - - - - 5.8 7.5 - - - - - - - - -
- - - - 6.2 7.4 - - - - - - - - -
STRJO - 1.1 1.1 1.1 2.0 4.7 - 0.4 4.0 2.0 - - - - -
- 2.1 - 2.0 - - - - - - - - - - -
- 1.6 - 6.0 4.0 6.0 0.5 4.0 5.7 0.5 1.3 - - - 1.0
YRJIL - 3.0 5.9 2.4 5.6 4.8 5.2 5.2 5.2 4.9 0.9 2.2 4.0 - 4.0
--------------------------------------------------------------------------------
Sum 21.0 58.0 53.0 56.2 92.7141.7103.0 87.6 84.3 71.8 44.0 15.1 23.0 24.2 64.4
3. Results (Meteors)
====================
Apr 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
--------------------------------------------------------------------------------
BRIBE 16 16 1 - - 12 3 - 13 10 2 - 2 13 7
CASFL - 2 - - - - 7 3 4 7 2 11 3 5 4
- 4 - - - - 6 3 7 4 - 8 4 9 5
CRIST - 15 24 - 18 - 8 15 1 - - 9 2 4 3
GONRU - - - - - 1 - 23 - 1 2 23 - - -
- - - - - 4 12 11 - 2 9 12 - - -
GOVMI - - - - - - - - - - - - - - -
HERCA 10 5 2 5 4 4 8 2 2 - - - 4 2 -
HINWO - - - - - 4 1 - 2 13 9 10 9 10 13
IGAAN - - - - - - - - - - - - - - -
- - - - - - 4 - - - - 14 - 10 14
JOBKL - - - - - - - - - - - - - - -
KACJA - - - 8 - - - 7 4 2 4 5 4 7 3
- - - 2 2 6 4 2 5 4 4 4 6 - 3
- - - 27 23 17 24 14 15 18 19 14 16 19 11
- - - - - - 5 6 1 - - - - - -
KOSDE - - - - - 2 - 8 3 - - - - - -
LUNRO 6 - - - 19 23 14 - - - - - 3 - -
MOLSI - 76 38 - - 17 19 - - - - - - - -
- 9 4 2 - 3 2 4 5 6 7 13 2 10 4
7 17 5 - 2 2 8 2 8 8 7 14 10 9 12
2 13 17 - 5 5 6 3 12 15 19 27 21 18 21
OCHPA - - 7 - 9 10 - 2 1 5 1 6 5 3 1
PRZDA 10 22 9 - 7 7 4 6 - 12 17 17 12 14 16
SLAST - - - - - - 2 - 2 3 - - - 2 7
STOEN - - - - 8 - 3 - - 6 2 13 8 4 4
3 19 - - 21 - 21 - - 19 7 26 15 12 14
2 16 - - 29 - 15 - 1 17 4 26 21 20 17
STORO - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - -
STRJO 7 7 2 - - 1 - 2 8 2 4 4 1 13 6
5 2 5 - - 1 - - 4 7 5 - - 2 3
10 9 7 - - 3 - - 17 2 9 9 7 7 4
YRJIL 9 - - - - - - 6 4 5 - - - 5 17
--------------------------------------------------------------------------------
Sum 87 232 121 44 147 122 176 119 119 168 133 265 155 198 189
Apr 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
--------------------------------------------------------------------------------
BRIBE - 4 4 17 26 22 - 14 12 1 - - 2 4 4
CASFL - - - - - 3 3 - 10 1 - - - - 1
- - - - - 12 4 - 10 - - - - - 9
CRIST 2 3 - - - 15 32 - - 1 - - 15 4 18
GONRU 2 - - - 31 36 27 24 - - 32 - - - 23
1 - - - 13 28 19 16 - - 12 - - - 15
GOVMI - - - - - - - - 17 26 - - - - -
HERCA 5 5 8 8 9 9 27 14 7 8 5 9 7 11 12
HINWO - 10 12 - 9 16 - 10 17 13 7 - - - -
IGAAN - - - - - 36 - 6 - 8 9 8 - 5 -
4 7 1 - - - - - - - - - - - -
JOBKL - - - - - - - - 47 - - - 41 17 11
KACJA - 6 2 - - 8 - - 8 4 - - - - -
- 1 - - - 16 7 - - 4 - - - - -
- - - - - - 22 - - 8 - - - - -
- - - - - - 6 - - 4 - - - - -
KOSDE - - 1 4 2 5 9 4 3 - - - - - -
LUNRO - 5 10 23 52 22 68 - - - - - - - -
MOLSI - - - 72 75 96 64 22 73 48 56 - - - -
- - 8 14 12 22 16 4 12 6 5 - - - 1
3 - - - - - - - - - - - - - -
5 - - - - - - - - - - - - - -
OCHPA - 3 - 1 14 3 2 9 2 - - - - 1 -
PRZDA - - 14 11 19 19 6 26 16 14 9 - - - -
SLAST - - 4 - - - 10 - - 4 - - - - -
STOEN - 5 - - - - 4 4 - - - - - - -
- 24 13 - - 25 14 10 - 3 - - - - 9
- 41 7 - - 47 11 19 - 4 - - - - 11
STORO - - - - 52 143 - - - - - - - - -
- - - - 52 121 - - - - - - - - -
STRJO - 3 2 1 4 6 - 1 5 3 - - - - -
- 5 - 3 - - - - - - - - - - -
- 4 - 13 20 17 1 12 10 1 2 - - - 2
YRJIL - 5 11 7 14 15 14 13 8 5 2 7 6 - 9
--------------------------------------------------------------------------------
Sum 22 131 97 174 404 742 366 208 257 166 139 24 71 42 125
Sirko Molau, 2009/05/28