Perseids 2024 - Installation of FHD meteor cameras in the CEMeNt network

At the beginning of 2024, the CEMeNt network (Central European Meteor Network) entered its sixteenth year of existence (Srba et al., 2016). Since 2009, 422,026 single-station meteors have been recorded in the CEMeNt network (as of 12/31/2023), from which 70,717 multi-station meteor orbits have been calculated. Since its inception, the network architecture has been based on CCTV (Closed-Circuit TeleVision) cameras, which works in 0.4 MPx resolution, and image transmission in the PAL (Phase Alternating Line) system is ensured by an analog path via a digital signal converter. The rapid development of recording technology in recent years, as well as the ever-higher requirements for the accuracy of calculated multi-station meteor trajectories, led to the fact that in July 2024 the replacement of these existing camera systems at stations of the CEMeNt network with modern CMOS (Complementary Meta-Oxide-Semiconductor) cameras with significantly higher sensitivity and also with a higher FHD (Full High-Definition) 2.1 MPx resolution began.

Camera systems and data processing – status until 2024

At the stations of the CEMeNt network, systems based on analog cameras with CCD (Charge-Coupled Device) Sony chips (1/2″ ExView HAD, 1/3″ Super HAD II) were used, i.e. on CCTV cameras Watec 902 H2 Ultimate, KPF 131 HR or VE 6047 EF with Goyo, Tokina or Tamron lenses (varifocal design, possibly with fixed focus). The signal in the PAL system had a resolution of 720 × 576 px (0.4 MPx) and a frame rate of 25 fps. Analog signal to digital conversion was implemented by converters (Dazzle, Aver Media, etc.) designed for USB 2.0 interface. All steps of recording and processing individual meteor records were implemented using the UFO Tools program package, which includes the UFO Capture program for recording meteors, UFO Analyzer for astrometry and photometry of meteors, and UFO Orbit, which is used to calculate multi-station meteor orbits (SonotaCo, 2009).

FHD systems for video meteor observation and data processing

Fig. 3: FHD system components before assembly. Author: VM Observatory

The newly designed system is based on the existing cable distributions and is fully unified, an identical composition of system elements is used at all stations. Another requirement was the possibility of using the OSD (On-Screen Display) menu, which enables direct fixed settings of the camera’s parameters without the need to select them directly in the camera driver or in DS (DirectShow) of the operating system. After two months of testing, a board camera with a Sony Starvis IMX 327 LQR CMOS chip was chosen as the capture element, which is controlled via the OSD menu (Fig. 3). The camera provides an analog FHD signal with a resolution of 1920 × 1080 px (2.1 MPx), the chip size is 1/2.8″, quantum efficiency 75%, and for the needs of the CEMeNt network, a variant with an NTSC (National Television System Committee) output analog signal was chosen with a frame rate of 30 fps. The high-aperture Starlight lens (f/0.95) with an aperture of M16 and a fixed focus (4 mm) is capable of rendering chips up to 1/2.7″ in size and provides a FOV (Field Of View) 89 (± 1) × 50°. The analog signal to digital conversion is realized in two stages. The existing cable distribution realized by a coaxial cable with a copper signal carrier (75 Ohm) is connected to the AHD/HDMI converter using a BNC connector. The second converter (HDMI/USB 3.2) converts the signal to the USB (up to 3.2) interface of the desktop computer with the help of the MS 2130 conversion chip and ensures sufficient capacity for transmitting the FHD signal at the required frame rate (Fig. 1). All steps of recording and processing individual meteor records are again implemented using the UFO Tools program package, which includes the UFO Capture HD program (for HD resolution and higher) for recording meteors, UFO Analyzer for astrometry and photometry of meteors and UFO Orbit, which is used for calculating multi-station meteor orbits.

CEMeNt – current status

Currently, the CEMeNt network in the Czech Republic consists of stations in Valašské Meziříčí (4 cameras), Vsetín (1), Maruška (2), Ždánice (2), Karlovy Vary (3, one camera currently out of service), Štípa (1), Plzeň (1) and Rokycany (1). In Slovakia, the stations Partizánske (2), Blahová (3), Jablonec (1), Kysucké Nové Mesto (1) and Zvolenská Slatina (1) are in operation (Fig. 2). As part of the first stage, new FHD cameras were installed at the Moravian stations, i.e. at the observatories of Valašské Meziříčí (Fig. 4), Vsetín, Ždánice (Fig. 5) and at the private stations Štípa and Maruška in the number of quality ones with the original PAL cameras. At the same time, both KPF 131 HR cameras were replaced by more sensitive Watec 902 H2 Ultimate cameras at the Partizánske Observatory. The Karlovy Vary Observatory has two Watec 902 H2 Ultimate cameras and one KPF 131 HR camera. KPF 131 HR cameras are also installed at the Rokycany Observatory, at the Plzeň station and in Slovakia at the Blahová and Zvolenská Slatina stations. Data from the CEMeNt network continues to be an integral part of the EDMOND database (European viDeoMeteOr Network Database), which brings together video data from meteor observations coming from 15 independent national networks and 2 transnational databases that use different methods and systems to detect meteors and also to calculate their orbits (Kornoš et al., 2013; 2014). Increasing the accuracy and sensitivity of recording devices thanks to the higher resolution of FHD cameras will contribute to improving the quality of the data stored in the EDMOND database.

Tab. 1: Overview of the number of recorded and matched meteors from 01/08/2024 to 13/08/2024 at the stations of the CEMeNt network. Author: Jakub Koukal

Perseids meteor shower – introduction

The Perseids meteor shower belongs, together with the January Quadrantids and the December Geminids, to the so-called big three, i.e. to the 3 strongest regular showers that we can observe during the year. Although the title of the strongest regular meteor shower currently belongs to the Geminids, the observation of the Perseids is attractive because of the maximum in August, when the observation of this shower is after all more accessible to the general public, unlike the two mentioned winter showers. The Valašské Meziříčí Observatory has been studying meteor tracks using video technology since 2011 and studying meteor spectra using video technology since 2014. During July 2024, the replacement of existing camera systems for studying meteor orbits at stations of the CEMeNt network with modern CMOS cameras with significantly higher sensitivity and also with a higher FHD 2.1 MPx resolution began. For this reason, the first results of the reconstructed network were eagerly awaited, and it was impossible to find a better period for testing the functioning of the network as a whole than the period of activity of the Perseids meteor shower.

Perseids 2024 in the CEMeNt network

The total number of meteors recorded during the Perseids 2024 campaign exceeded expectations. A total of 14,999 single-station meteors were recorded, from which 3,758 orbits were calculated (Tab. 1, Fig. 6). More than half were multi-station meteor tracks belonging to the Perseid meteor shower, the total number of multi-station tracks of this shower was 1,917 (Fig. 7). For comparison, in the entire CEMeNt network, 21,673 single-station meteors were recorded during the entire year 2021, then 21,311 single-station meteors in 2022, and in 2023, only 18,891 single-station meteors. The pairing efficiency is 63.7 %, which represents a more than double increase in efficiency compared to previous years. The station/orbit ratio increased to 2.54, which means that one multi-station orbit accounts for an average of more than 2.5 meteor records from individual cameras. This fact significantly increases the accuracy of the calculation of multi-station orbits, when clear fireballs have 8 or more records from individual stations, and therefore only the most geometrically favorable ones can be used.

Fig. 8: Histogram of distribution of relative magnitudes (bin 0.25m) of meteors from stations Valašské Meziříčí NE (FHD IMX 327) and Partizánske NE (Watec 902 H2). Both cameras have comparable FOV center azimuth and elevation, and the histogram shows the shift in magnitude limit and maximum magnitude distribution in the case of the new FHD system. Author: Jakub Koukal

Overall, the full operation of the new FHD cameras in the CEMeNt network can be evaluated excellently, as the number of recorded meteors has significantly increased (~2.5×), as well as the limit magnitude for their recording has decreased (+4.0m, the existing Watec 902 H2 system reaches +2.5m) and the average accuracy of measuring the meteor’s trajectories has also increased (~3×). This result is achieved both thanks to the higher resolution of the cameras and also thanks to the greater dynamics of the IMX 327 chips, when there is no saturation of bright meteors (fireballs) to the extent that this is the case with the Watec 902 H2 cameras.

Composite Images of Meteors Recorded by FHD IMX 327 Systems

Composite Images of Meteors Recorded by Watec 902 H2 Systems

The Perseids meteor shower activity also tends to be rich in fireballs bright enough to record their spectra. Simultaneously with this shower, other meteor showers are active, for example the kappa Cygnids or the alpha Capricornids, which often produce fireballs and are recorded on spectrographs at the Valašské Meziříčí Observatory. A total of 13 spectra from 10 individual fireballs were recorded during the Perseid 2024 campaign, with all spectra belonging to fireballs belonging to the Perseid meteor shower this year.

References

Kornoš L., Koukal J., Piffl R., and Tóth J. (2013). Database of meteoroid orbits from several European video networks. Proceedings of the International Meteor Conference, La Palma, Sep. 20-23, 2012, eds. Gyssens M., Roggemans P., International Meteor Organization, p. 21-25.
Kornoš L., Koukal J., Piffl R., and Tóth J. (2014). EDMOND Meteor Database. Proceedings of the International Meteor Conference, Poznań, Poland, Aug. 22-25, 2013, eds. Gyssens M., Roggemans P., International Meteor Organization, p. 23-25.

SonotaCo (2009). A meteor shower catalog based on video observations in 2007-2008. WGN, Journal of the International Meteor Organization 37:2, 2009, p. 55-62.

Srba J., Koukal J., Ferus M., Lenža L., Gorková S., Civiš S., et al. (2016). Central European MetEor NeTwork: Current status and future activities. WGN, Journal of the International Meteor Organization, 44(3), p. 71-77.

Acknowledgment

Thanks go to the companies DEZA, a. s. and CS CABOT, spol. s. r. o., which contributed to the acquisition of equipment for FHD stations located at Valašské Meziříčí Observatory and also within the CEMeNt network. Thanks to all partner observatories (Ždánice, Vsetín, Rokycany, Plzeň, Karlovy Vary, Partizánske, Kysucké Nové Mesto) as well as private station owners (Milan Čermák, Richard Káčerek, Jakub Kapuš, Tibor Csorgei, Vladimír Bahýl) for supporting the activities and growth of the network. Thanks also go to all interested institutions for supporting the activities and growth of the network. The RPOS project (Development of a cross-border observation network) was co-financed from the Small Projects Fund of the Interreg V-A Slovak Republic – Czech Republic 2014 – 2020 program, call code 5/FMP/11b, reg. no. CZ/FMP/11b/05/058. The projects KOSOAP (Cooperative network in the field of astronomical expert-observation programs) and RPKS (Development of a cross-border cooperative network for professional work and education) were implemented by the observatories Valašské Meziříčí (CR) and Kysucké Nové Mesto (SR) in cooperation with SMPH (Society for Interplanetary Matter). The projects were co-financed from the micro-project fund of the Slovak Republic – Czech Republic 2007-2013 Border Cooperation Operational Program. The project for the purchase and operation of high-resolution spectroscopic cameras is partially subsidized by the Regional Cooperation Program of the Academy of Sciences of the Czech Republic, reg. no. R200402101 and grant APVV-0517-12 (FMFI UK).