1. Institute of Physics, Faculty of Science, Ss. Cyril and Methodius University, Skopje, Republic of Macedonia
2. Astronomical Observatory, Belgrade, Serbia
3. Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences, Sofia, Bulgaria
4. Armagh Observatory and Planetarium, College Hill, Armagh, Northern Ireland, UK + Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences, Sofia, Bulgaria