[1] Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kačićeva 26, 10000 Zagreb, Croatia
[2] Kiepenheuer-Inst. Sonnenphys. (KIS), Schöneckstr. 6, 79104 Freiburg, Germany
[3] Observatoire Royal de Belgique (ORB), Av. Circulaire 3, 1180 Bruxelles, Belgium