Royal Observatory of Belgium was first established in Saint-Josse-ten-Noode in 1826 by William I. It is a scientific research institute, which also provides a wide range of services. Researchers study the planet Earth and other, near and distant objects in space. Scientists at the observatory are involved in the following fields: astronomy, astrophysics, space geodesy and solar physics. The main activities are Reference systems and geodynamics, Astrometry and dynamics of celestial bodies, Astrophysics and Solar physics. The Royal Observatory of Belgium also runs the Planetarium, known for its large dome (at a diameter of more than 23 metres, one of the largest in Europe) on the Heysel. Audiences are able to gaze at the starry sky with the help of special audiovisual programs. The national scale of the Planetarium is well known abroad: it hosts the European Space Education Resources Office (ESERO), it is the press contact point for the European Southern Observatory (ESO), and also the coordinator of the Belgian activities for the International Astronomical Union (IAU) and it is involved in many other European educational projects. The Royal Observatory of Belgium is having 51-200 employees. It was home to a 100 cm diameter aperture Zeiss reflector in the first half of the 20th century, one of the largest telescopes in the world at the time. The goal of OD Solar Physics and Space Weather research activities is to increase our understanding of the Sun and its influence on the solar system. The specific topics that we aim to research are inspired by our own operational activities, by our heritage in some sub disciplines and -last but not least- by a passion for understanding the Sun and its effects at a more fundamental level. It owns a variety of other astronomical instruments, such as astrographs, as well as a range of seismograph equipment for detecting earthquakes. The missions of the Operational Direction “Reference Systems and Planetology” is to contribute to the elaboration of reference systems and timescales, theoretically as well as observationally, to integrate Belgium in the international reference frames (concerning space geodesy and time), to obtain information on the Earth’s interior, rotation, dynamics, and crustal deformation, at the local, regional, and global levels and to study the interior structure, evolution, and dynamics of other terrestrial planets and moons of the solar system.