In 2004, the following guests visited our institute: P. Ambroz (Astronomical Institute, Ondrejov, Czech Republic), J. Boška (Institute of the Atmospheric Physics, Prague, Czech Republic), A. Budovicová (Astronomical Institute, Ondrejov, Czech Republic), G. Cevolani (ISAC (FISBAT) CNR, Bologna, Italy), I. Iliev (Rozhen Observatory, Bulgarian Academy of Sciences, Sofia, Bulgaria), A. Kawka (Astronomical Institute, Ondrejov, Czech Republic), D. Korcáková (Astronomical Institute, Ondrejov, Czech Republic), P. Krizan, Institute of the Atmospheric Physics, Prague, Czech Republic), K. Krticka (Astronomical Institute, Ondrejov, Czech Republic), J. Kubát (Astronomical Institute, Ondrejov, Czech Republic), D.O. Kudrjavcev (SAO RAN, Russia), J. Laštovicka (Institute of the Atmospheric Physics, Prague, Czech Republic), Z. Mikulášek (Institute of Theoretical Physics and Astrophysics, Masaryk University, Brno, Czech Republic), J. Pettingrew (University of Queensland, Brisbane, Australia), P. Pracna (J. Heyrovský Institute of Physical Chemistry, Prague, Czech Republic), G. Pupillo (ISAC (FISBAT) CNR, Bologna, Italy), J.I. Romanjuk (SAO RAN, Russia), S. Shugarov (Sternberg Astronomical Institute, Moscow State University, Moscow, Russia), T. Šindelárová, Institute of the Atmospheric Physics, Prague, Czech Republic), P. Škoda (Astronomical Institute, Ondrejov, Czech Republic), J. Streštík (Geophysical Institute, Prague, Czech Republic), M. Temmer (IGAM, University of Graz, Graz, Austria), V. Votruba (Astronomical Institute, Ondrejov, Czech Republic), I. Volkov (Sternberg Astronomical Institute, Moscow State University, Moscow, Russia).