(September 12, 1940 at Písek, Czech Republic)
Specialization and most important results: Numeric treatment of observed data, especially of astrometric observations of Earth rotation parameters (smoothing method), orbital motion of the Moon and rotational dynamics of the Earth (tidal and rotational deformations, planetary effects in precession-nutation, atmospheric excitation of polar motion and speed of rotation), cooperation on linking the Hipparcos Catalogue to extragalactic system, calculation of ephemeredes of celestial objects, combination of Earth orientation parameters by different space techniques, derivation of astrometric star catalogues from combination of Hipparcos and ground-based observations, studies of geophysical excitations around free core nutation resonance. About 300 scientific papers published.
- 1957-1962 studies at the Faculty of Civil Engineering, Czech Technical University, Prague (Geodesy, geodetic astronomy)
- 1962-1964 Geodetical and Topographical Institute, Prague
- 1965-1977 Research Institute for Geodesy, Topography and Cartography in Prague (Geodetical Observatory Pecný)
- 1973 PhD. thesis Determination of ephemeris time and lunar orbital elements by the method of equal altitudes
- Since 1977 at the Astronomical Institute, Academy of Sciences of the Czech Republic
- Since 1979 member of the International Astronomical Union (IAU)
- 1983 three-month stay at the Bureau International de l'Heure
- 1985 DSc. thesis More accurate theory of lunar motion and solution of the modern problems of rotational dynamics of the Earth's body
- 1988-1997 chairman of the IAU Working group on Earth rotation in the Hipparcos reference frame
- 1989 three-month stay at the U.S. Naval Observatory, Washington DC (Dept. of Time Service and Earth Orientation)
- Since 1990 member of American Geophysical Union
- 1991 founding member of European Astronomical Society
- 1991-2000 Head of the Department of Dynamical Astronomy at the Astronomical Institute
- 1991/1992 six-month stay at Observatoire de Paris (Dept. of Fundamental Astronomy)
- 1992-1997 Principal Investigator of Earth rotation in the Hipparcos reference frame
- 1994-1997 President of IAU Commission 19
- 1998-2004 Chairman of the Czech National Astronomical Committee
- 1999 two-month stay at Observatoire de Paris (Dept. of Fundamental Astronomy and Central Bureau of IERS)
- 1998-2004 IAU Representative to the Directing Board of the International Earth Rotation Service
- 2000 Head of the team awarded by the Prize of the Academy of Sciences of the Czech Republic for Solution of Earth Orientation Parameters in 1900-1992
- 2000-2005 Vice-director of the Astronomical Institute for foreign relations
- 2001-2004 Chairman of the Directing Board of the International Earth Rotation Service
- 2003-2006 Vice-president of IAU Division I (Fundamental Astronomy)
- 2003 Ernst Mach Medal of Academy of Sciences of the Czech Republic for merits in physical sciences
- 2003 Member of international team awarded Descartes Prize by European Commission
- 2005-2010 the Czech National Representative to ICSU
- 2006-2009 President of IAU Division I (Fundamental Astronomy)
- 2007 Nul prize of the Czech Astronomical Society for life-long merits for astronomy
- 2008 asteroid No. 35356 named Vondrak (1997 SL3)
- Since 2010 chairman of the Czech Astronomical Society
- 2011 Dr. Honoris causa of Paris Observatory