1. Nicolaus Copernicus Astronomical Center, Bartycka 18, Warsaw, PL-00-716, Poland
2. Physics and Astronomy College of Charleston, 66 George Street, Charleston, SC 29424, USA
3. LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, F-92195 Meudon, France