Perseids 2004
Results of the IMO Video Meteor Network - August 2004
by Sirko Molau (Internationa Meteor Organisation)
Perseids 2004
Results of the IMO Video Meteor Network - August 2004
by Sirko Molau (Internationa Meteor Organisation)
Since what we have seen so far in 2004 was not so impressive, it's no wonder that August outbeated the previous months by far. Firstly, the number of observers and operated video cameras increased (the summer break of Ilkka Yrjola is over and we also received Perseid observations from Ondrejov observatory again). Secondly, nights were getting longer again, and finally the average number of meteors per hour increased by a factor of three compared to the first half of the year. Last but not least, there has been a new and very effective camera named AVIS2 in operation.
After the image intensifer of my old camera AVIS reach the end of lifetime earlier this year (after all, the second hand tube yielded about 5,000 hours of observing time in his "second life" and secured more than 26,000 meteors), I was looking for an replacement tube. At EBAY, there are regularly offers of identical tubes at reasonable rates, but most of them are sold in the US and cannot be exported. After some time I got a used Philips XX1332 for about Euro 200 from an UK dealer (www.abex.com). That's a second generation tube with a large photo cathode of 50 mm diameter. After I adapted my camera, AVIS2 saw first light during the Perseid campaign. At first I noticed, that contrary to other MCPs this tube shows some vignetting, which was not caused by the small format camera lens. Then I realized, that using the same objective lens the size of the fov had doubled, whereas the gain was at least as good as that of the old tube. In result, I achieved a 95 degree field of view with a remarkable limiting magnitude of 6 mag with my 35 mm f/2.0 lens. It came as no surprise, that the number of meteor records was correspondingly great. In fact, it was for the first time that my camera recorded in the same time interval more meteors than me!
All in all, I can only recommend this tube. Of course, image-intensified cameras are more expensive, less robust and have a shorter life time. However, their efficiency is still unbeated, especially away from larger showers.
Beside the surprising results of AVIS2 there was also some misfortune in August: When I was at the AKM Perseid camp in Ketzuer, MINCAM1 was operated automatically at my home. However, Murphy was active and let the camera fail for unknown reason just in the days around the Perseid maximum.
What about the observing results? Esko Lyytinen, who became well-known by his precise Leonid predictions, had forcasted enhanced Perseid activity for August 11, around 23 UT, caused by the one-revolution dust trail. Thus, the observers were especially alerted and fortunately the weather was cooperative at many sites. Visual observations in Europe yielded high Perseid activity in the first hours of the night, which reduced later somewhat but increased again towards the morning. Taking the low radiant at observation start into consideration it was immediately clear, that the activity early in the night was higher than usual. This was clearly confirmed by first analyses of visual observations. Some video observers, however, reported no enhanced activity at first. Later it became clear, that they had simply forgotten to correct for the low radiant altitude.
I created a graph (http://www.molau.de/temp/per04.gif) of all video observations available to me, which were not affected by clouds (except for AVIS2, where at some time a small cloud correction was applied), and which covered the early maximum. In addition to the data of the IMO network, I included an observation by Enrico Stomeo of Italy, who had inspected his video observation manually. Meteor counts were binned in 5 min intervals and corrected for the radiant altitude. Since the individual data sets are statistically independent of each other, all graphs were finally added. The resulting activity curve made of more than 500 Perseids shows fewer random fluctuations and a clear maximum.
The more meteors each camera recorded, the better the early peak becomes visible. In the overall activity graph maximum activity occurs in the 21:05-21:10 UT interval. It stands clearly out of the background, i.e. (almost) all cameras recorded more meteors in that time interval than before or after. Interestingly, there is a difference of almost 10 minutes to the visual observations, whose activity graph made of 30 times more meteors peaked at 20:56 UT.
1. Observers
============
Code Name Place Camera FOV LM Nights Time Meteors
--------------------------------------------------------------------------------
EVAST Evans Moreton RF1 (1.2/12) 20 dg 4 mag 11 71.6 h 447
KACJA Kac Kostanjevec METKA (0.8/8) 55 dg 4 mag 16 95.6 h 426
KOSDE Koschny Noordwijkerh. ICC3 (0.85/25) 25 dg 6 mag 6 33.3 h 359
ICC2 (0.85/25) 25 dg 6 mag 1 3.0 h 44
MOLSI Molau Seysdorf AKM1 (0.85/25) 32 dg 6 mag 11 53.4 h 238
MINCAM1 (1.4/12) 35 dg 4 mag 22 121.1 h 266
Ketzuer AVIS2 (2.0/35) 95 dg 6 mag 9 39.4 h 927
SLAST Slavec Ljubljana KAYAK1 (1.8/28) 50 dg 4 mag 16 81.9 h 487
STORO Stork Ondrejov OND1 (2.4/35) 70 dg 3 mag 3 18.4 h 123
STRJO Strunk Leopoldshoehe MINCAM2 (0.8/8) 42 dg 4 mag 24 98.5 h 498
MINCAM3 (0.8/6) 55 dg 3 mag 12 70.3 h 443
UEBST Ueberschaer Aachen MIMO (0.95/25) 13 dg 4 mag 6 29.7 h 84
YRJIL Yrjola Kuusankoski FINEXCAM (0.8/6) 50 dg 3 mag 13 51.9 h 404
--------------------------------------------------------------------------------
Sum 30 768.1 h 4746
2. Observing Times (h)
======================
Aug 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
--------------------------------------------------------------------------------
EVAST 5.0 - - 5.4 - 5.9 5.8 - - - - 6.0 - 6.4 -
KACJA - - - 6.1 6.1 - - - 6.3 7.1 7.5 3.0 0.6 4.1 7.3
KOSDE - 5.0 - 5.6 - - - 5.0 4.3 - 7.6 - - - -
- - - - - - - - - - 3.0 - - - -
MOLSI - - 4.6 4.5 6.6 4.4 5.2 6.7 - - - - - - -
2.2 - 7.4 6.5 7.4 3.5 7.5 7.6 - 3.7 - - - - 8.0
- - - - - - - - 3.0 5.0 6.0 1.1 - 6.3 6.3
SLAST - - - - - - - - - 3.5 6.8 - - 3.5 4.6
STORO - - - - - - - - 5.8 6.2 6.4 - - - -
STRJO 5.5 5.9 3.2 3.9 5.9 6.0 6.1 4.7 6.2 - 6.4 0.5 3.6 2.3 4.1
5.4 5.5 5.8 - 5.9 6.5 5.9 - 6.0 - 6.1 - - - -
UEBST - - - - 7.4 - - - 6.7 0.5 8.6 5.5 - - -
YRJIL - - - - - - - - - 3.3 4.0 3.3 2.6 3.1 2.6
--------------------------------------------------------------------------------
Sum 18.1 16.4 21.0 32.0 39.3 26.3 30.5 24.0 38.3 29.3 62.4 19.4 6.8 25.7
32.9
Aug 16 17 18 19 20 21 22 23 24 25 26 27 28 29
30 31
-------------------------------------------------------------------------------------
EVAST - - - 6.8 - - - - - - - 7.6 - 7.0
7.9 7.8
KACJA 7.1 7.6 7.8 - - - - 4.7 - - - 7.8 8.5 4.0
- -
KOSDE - - - - - - 5.8 - - - - - - -
- -
- - - - - - - - - - - - - -
- -
MOLSI - - - - 0.4 - 6.0 - 5.3 - - 7.6 2.1 -
- -
7.1 8.1 8.2 - 1.3 1.4 6.4 6.2 8.6 0.6 - 8.8 4.3 3.9
- 2.4
- 6.3 3.4 2.0 - - - - - - - - -
- -
SLAST 6.7 7.1 7.0 6.8 - - 5.3 7.7 5.1 0.7 - 4.5 4.6 6.0
2.0 -
STORO - - - - - - - - - - - - - -
- -
STRJO 0.7 0.5 0.7 6.9 1.0 7.0 7.0 3.5 0.5 - - - - -
- 6.4
- - - - - 6.1 7.2 3.1 - - - - - -
- 6.8
UEBST - - - - - - - - - - - - - -
1.0 -
YRJIL - 3.7 4.7 - - 3.3 4.7 5.3 5.5 - - - - 5.8
- -
-------------------------------------------------------------------------------------
Sum 21.6 33.3 31.8 22.5 2.7 17.8 42.4 30.5 25.0 1.3 - 36.3 19.5 26.7 10.9
23.4
3. Results (Meteors)
====================
Aug 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
--------------------------------------------------------------------------------
EVAST 31 - - 18 - 40 55 - - - - 102 - 37 -
KACJA - - - 8 15 - - - 42 41 155 11 2 18 24
KOSDE - 44 - 37 - - - 51 58 - 139 - - - -
- - - - - - - - - - 44 - - - -
MOLSI - - 7 31 22 18 38 35 - - - - - - -
5 - 5 22 23 12 18 30 - 6 - - - - 19
- - - - - - - - 83 131 363 17 - 173 78
SLAST - - - - - - - - - 27 131 - - 7 43
STORO - - - - - - - - 36 25 62 - - - -
STRJO 22 23 13 12 25 20 34 28 43 - 142 2 10 7 11
14 24 15 - 33 26 27 - 45 - 181 - - - -
UEBST - - - - 8 - - - 13 1 53 7 - - -
YRJIL - - - - - - - - - 38 150 33 11 31 14
--------------------------------------------------------------------------------
Sum 72 91 40 128 126 116 172 144 320 269 1420 172 23 273
189
Aug 16 17 18 19 20 21 22 23 24 25 26 27 28 29
30 31
-------------------------------------------------------------------------------------
EVAST - - - 25 - - - - - - - 46 - 17
29 47
KACJA 15 30 21 - - - - 10 - - - 10 17 7
- -
KOSDE - - - - - - 30 - - - - - - -
- -
- - - - - - - - - - - - - -
- -
MOLSI - - - - 3 - 25 - 22 - - 33 4 -
- -
10 12 18 - 1 1 9 13 19 1 - 19 8 10
- 5
- 49 16 17 - - - - - - - - - -
- -
SLAST 32 33 32 27 - - 40 30 16 2 - 29 19 16
3 -
STORO - - - - - - - - - - - - - -
- -
STRJO 3 2 3 19 5 25 20 9 2 - - - - -
- 18
- - - - - 28 25 6 - - - - - -
- 19
UEBST - - - - - - - - - - - - - -
2 -
YRJIL - 10 18 - - 17 21 21 22 - - - - 18
- -
-------------------------------------------------------------------------------------
Sum 60 136 108 88 9 71 170 89 81 3 - 137 48 68
34 89
************************************************************
* Sirko Molau * *
* Abenstalstr. 13b * __ *
* D-84072 Seysdorf * " 2B v 2B " *
* Germany * *
* phone: +49-8752-869438 * Shakespeare *
* email: sirko@molau.de * *
* www : www.molau.de * *
************************************************************
Grafico realizzato da Sirco Molau con tutte le osservazioni disponibili, considerate le correzioni per le altezze del
radiante, e una curva sommatoria di piu' di 500 Perseidi, dalla quale appare evidente che il picco video di attivitą č
avvenuto alle 2105-2110 UT, cioe' quasi 10 minuti dopo di quello registrato visualmente (cortesia Sirco Molau; il
commento č di Enrico Stomeo, esponsabile UAI-sm).
Con una punta di giusto orgoglio, Stomeo fa notare che questa analisi di dati video raccoglie per la prima volta anche le
osservazioni di alcuni osservatori italiani.
