1. Astronomical Institute of the Wrocław University, Kopernika 11, PL-51-622 Wrocław, Poland
2. Copernicus Astronomical Center, Bartycka 18, PL-00-716 Warsaw, Poland
3. Département de physique, Université de Montréal, Montréal QC H3C 3J7, Canada
4. Department of Electronics, Electrical Engineering and Microelectronics, Silesian University of Technology, Akademicka 16, PL-44-100 Gliwice, Poland
5. Department of Physics and Space Science, Royal Military College of Canada, PO Box 17000, Station Forces, Kingston, ON K7K 7B4, Canada
6. Institute for Astro- and Particle Physics, Universität Innsbruck,Technikerstrasse 25, A-6020 Innsbruck, Austria
7. American Association of Variable Star Observers, 49 Bay State Road, Cambridge, MA 02138, USA