1. Research Center for Astronomy and Applied Mathematics, Academy of Athens, 15126 Athens, Greece
2. Mariolopoulos-Kanaginis Foundation for Environmental Research, 10675 Athens, Greece
3. Institute of Electronics, AGH University of Krakow, 30-059 Krakow, Poland
4. Astronomical Observatory, Jagiellonian University, 30-244 Krakow, Poland
5. Electronics-Telecommunications and Applications Laboratory, Physics Department, University of Ioannina, 45110 Ioannina, Greece