Database of Meteor Orbits from several European Video Networks

EDMOND (European viDeo MeteOr Network Database) is a database of orbits based and computed upon the high definition video data of observed meteor showers. It is a result of cooperation and data sharing among seven national networks. This is the first version containing processed data from individual stations by years 2009, 2010, 2011 and first half of 2012 (until June 30, 2012). 59 stations contributed 267,850 single-station meteors to this database up-to-date. However, this number is not complete, data from several stations are still being processed. Combined observations delivered 25,112 reliable orbits which are published in the first version of the EDMOND database.

Introduction

Almost in every European country there is a network of video or photographic meteor observation. In many of them there are also created their own databases of meteor orbits when they obtain double or multi-station observation of meteors. But singe-station meteors still remain unused. So it is important to try to find as many as possible common meteors through all neighbouring networks.

EDMONd map

Figure 1 – Location of ground-based video meteor stations of SVMN, CEMeNt, PFN and IMTN in the northern Italy during the Draconids 2011.

Joined Network

The European viDeo Meteor Observation Network (EDMONd) has been established only recently. The network originated spontaneously based on cooperation between observers in several parts of Europe. Nowadays, EDMONd consists of observers from following national networks (in alphabetical order) – BOAM (French amateur observers France BOAM network / Base des Observateurs Amateurs de Météores), CEMeNt (Central European Meteor Network, cross-border network of Czech and Slovak amateur observers), HMN (Hungarian amateur observers, Hungarian Meteor Network / Magyar Hullócsillagok Egyesület), IMTN (Italian amateur observers in Italian Meteor and TLE network), PFN (Polish Fireball Network / Pracownia Komet i Meteorów, PkiM), SVMN (Comenius University network, Slovak Video Meteor Network) and UKMON (British amateur observers, UK Meteor Observation Network).

The cooperation between individual networks has begun in 2009 when first orbit was derived based on shared observations of the same meteor by CEMeNt and SVMN. In spring 2010 we contacted Polish and Hungarian networks (PFN and HMN). First data were obtained, combined and assessed by using di®erent detection and processing tools (UFO Tools, MetRec). In the second half of 2011 EDMONd incorporated Italian stations (IMTN) within the Draconid 2011 observing campaign. As a result of this cooperation, there was a paper presenting precise orbits of meteoroids associated with the comet 21P/Giacobini-Zinner (Tóth et al. 2012). Inspired by productive cooperation, British network UKMON was established in 2012 which shared the observing space with the French network (BOAM). This is the latest national network included in the EDMONd network (Figure 1).

2009-2012

Meteor activity from all stations.

Amateur stations mostly use sensitive analog CCTV cameras based on Sony chips 1/2″ ExView HAD, 1/3″ Super HAD) with the typical resolution of 720 × 576 pixels and lens with the focal length of 3 – 8 mm with the focal ration of f/0.8 – f/1.4. Most of the stations uses UFOCapture (from UFO Tools of SonotaCo, 2009) software for automated meteor recognition with the exception of the Hungarian (HMN) which uses MetRec (Molau, 1999) package. The typical field of view is ± 70° horizontally. These stations are able to detect meteors brighter than +2.5 mag. However, the detection e±ciency and sensitivity depends on the combination of the CCTV camera, lens and local sky conditions at the observing site.

The number of stations in national networks and single meteors shared in EDMONd network are presented in (Table 1).

Table 1

Table 1 – Number of stations in particular networks and single meteors shared in EDMONd network.

New database of orbits

Presented database of meteor orbits is a result of newly established international network EDMONd of video meteor observers. Meteor data in the database are obtained by various instruments and processing tools (MetRec and UFO Tools).

First of all it was necessary to convert MetRec data to the UFOOrbit format. The MetRec data were imported via the conversion software INF2MCSV written by SonotaCo (http://sonotaco.com/soft/e index.html). This program supports several conversion methods. To obtain the optimal coincidence with the UFOAnalyzer results, we tested 230 double station meteors detected in a straight campaign between April and June 2011 where one station was using MetRec and the second UFOCapture. Resulting data were uploaded into UFOOrbit. Final UFOOrbit output generated also the quality parameter (QA), duration of a meteor (dur) and geocentric velocity (Vg) which have been assessed.

Radiants

Whole radiants of 37,392 multi-stations meteors.

Following the quality parameter (QA) and (dur) and (Vg), the analysis shows that the best criterion for data conversion from MetRec to csv file for UFOOrbit is the transfer method (Y). This method provides the most close data with respect to the UFOAnalyzer output, errors with respect to (Vg) and (dur) are minimized. Hence, this procedure is applied to the Hungarian station (HMN) data which constitute 35% of all EDMOND entries.

Output csv files from UFOAnalyzer by individual stations are obtained and assembled by national coordinators. Data analysis is mostly done by individual observers and results are sent to national coordinators (Stéphane Jouin, BOAM; Jakub Koukal, CEMeNt; Igaz Antal, HMN; Ferruccio Zanotti, IMTN; Przemyslaw Zoladek, PFN; Juraj Tóth, SVMN; Richard Káčerek, UKMON). Coordinators share data on the common ftp server. MetRec conversion is done by Jakub Koukal.

The main computation of orbits is done by UFOOrbit software. UFOOrbit allows multiple parameters setting. Our database contains unfiltered data obtained by setting (Q0). Meteors are coupled only when the time of the suspected meteor does not differ more than 5 seconds. The (Q0) parameter provides all possible combinations and difference dt = 5 sec was chosen because several stations had some problems with a correct time setting. Thus we have got about 37 000 orbits.

Of course, there are many fictional orbits (also according to SonotaCo, personal communication) in this set. So the cleaning was necessary. The selected parameters used to clean the database in two steps are presented in (Table 2). In the first step we setup beginning and terminal heights and overlapping parameter Gm% (the value -100% was taken from SonotaCo, personal communication), where the negative value means that the two stations do not see the same part of observed meteor.

Table 2

Table 2 – The values of parameters that are used and their description according to SonotaCo (2009 and manual).

In the second step, the values of the selected parameters were set not too strictly so we could obtain as many as possible real orbits. In this way we have obtained more than 25,112 meteor orbits. This database has been named EDMOND – European viDeo MeteOr Network Database.

There are 21 833 double-station orbits, 2 666 three-station, 527 four-station and 148 five-station orbits in the database. The precision of multi-station orbits has not been analyzed yet. There have also been identified 15 870 sporadic / 9 385 shower meteors in the database, from them 33 established and 22 working showers according to IAU Meteor Data Center (with 10 and more meteors in the database).

We performed a small analysis of the EDMOND database (Figure 2 and 3). The parameter dv12% means the difference between the unified velocity and velocity from one of observing stations. The parameter is very important as the difference in velocity about 10% is very large.

Figure 2a

Figure 2a – Distribution of the difference of two velocities (dv12%), the unified velocity and the velocity of one of the observing stations – EDMOND.

Figure 2b

Figure 2b – Distribution of the difference of two velocities (dv12%), the unified velocity and the velocity of one of the observing stations – SonotaCo Q1 2009 database.

So we have compared the distribution of the parameter dv12% in our database with the distribution in SonotaCo Q1 2009 database. As can be seen (Figure 2), the drop of the number of meteors with increasing dv12% in SonotaCo database is faster than in EDMOND, which prefers SonotaCo data. On the other hand, SonotaCo database contains also meteors with much larger value of dv% than 10%. From our database such meteors are removed.

Figure 3

Figure 3 – Dispersion of orbital parameters (eccentricity and inclination) of Lyrids in database EDMOND (up) and SonotaCo Q1 2009 (down).

We have also compared the dispersion of orbital elements e; i of Lyrids in both databases. The identification of a meteor with the stream is taken from SonotaCo. The SonotaCo database also includes several meteors which are a little off, but the core of the element’s dispersion (both e and i) is less spread than the core in the new database.

4 Conclusions

In spite of a lower precision, we can highlight that the EDMOND data are compiled from 7 networks, 59 stations and there were obtained 25 255 orbits within 2009 – 2012 yrs. The data have not been used to compute meteor orbits yet.

A less consistency of data in EDMOND may be caused by several factors:

– different equipment (resolution, analog / digital)
– different processing tools (MetRec, UFO)
– measurement experience

More detail analysis of obtained precision will be done in the future. For example, the SVMN and CEMeNT observations were several times confronted with the most precise photographic data obtained by the European Bolide Network, operated by the Ondřejov Observatory, the Astronomical Institute of the Academy of Sciences of the Czech Republic. Our data are only about one half of order less precise in comparison with the photographic data.

The new database EDMOND joined many observers and it has potential to be improved and enlarged.

Acknowledgements

The work was supported by the grant VEGA 1/0636/09, APVV-0516-10 grant. We greatly appreciate the help of professional and amateur astronomers who provided the video observations and data analysis. We also appreciate a broad international cooperation and smooth data sharing.

References

Molau S. (1999). „The meteor detection software MetRec“. In Arlt R. and Knoefel A., editors, Proc. IMC 1998, Stará Lesná, pages 9-16. IMO.

SonotaCo (2009). „A meteor shower catalog based on video observations in 2007-2008“. WGN, Journal of the IMO, 37, 55-62.

Tóth J., Piffl R., Koukal J., Zoladek P., Wiśniewski M., Gajdoš S., Zanotti F., Valeri D., De Maria P., Popek M., Gorková S., Világi J., and Kornoš L. (2012). „Video observation of Draconids 2011 from Italy“. WGN, Journal of the IMO, 40, 117-121.

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