Towards the mid XIXth C., the property of Constantin Bosianu appeared in the Filaret Hill area, where the Astronomical Institute is located today. Constantin Bosianu (1815-1882) was a politician who held over time a number of high state positions: Prime-Minister, Mayor of Bucharest, Minister of Internal Affairs, personal counselor of the first Ruler of modern Romania, Alexandru Ioan Cuza, and honorary member of the Romanian Academy.
In 1884, the Meteorological Institute of Romania was founded by the meteorologist and physicist Ştefan Hepites and started the activity on the same location.
At the end of the XIXth C., several scientific buildings were constructed here, having mainly a meteorological purpose. Among them, the Small Meridian Hall (1893) was the first permanent building in Romania designated for astronomy use.
On the 1st of April 1908, the Minister of Public Instruction and Religious Affairs, Spiru Haret, signed the Decree for the founding of the Meteorological and Astronomical Observatory in Bucharest, under the leadership of Nicolae Coculescu, the director of the Observatory between 1908-1938.
The architectural project of the main building of the Observatory, comprising an Equatorial Dome and a Meridian Hall, was realized by the Belgian architect Adolphe Engels, while the engineer Mihail Roco was in charge with the coordination of the construction team. In 1912, the building became functional but without a complete fulfilment of all the parts of the architectural blueprints.
In 1920, the Observatory was reorganized and the scientific branches comprising it, namely meteorology and astronomy, were separated into two distinct institutions: the Astronomical Observatory and the Meteorological Central Institute. During the interwar period, the scientific activities undertaken here led to remarkable achievements, and they were done by a number of research scientists who were also university professors. Among them were: Nicolae Coculescu, Gheorghe Demetrescu, Gheorghe Petrescu, Constantin Drâmbă, Călin Popovici.
In 1922, Romania joined the International Astronomical Union (IAU) and in 1930 the Romanian National Astronomical Committee (RNAC) was created as a scientific organization for the promotion of astronomy. The committee prepared the Bucharest Observatory’s participation to the international campaign of longitude measurements, in 1933, and for this purpose a new scientific equipment was purchased and installed in the basement of the main building of the Observatory.
The activity of the Astronomical Observatory was greatly diminished during World War II, but without being completely stopped. In these tragic circumstances, Constantin Popovici, who was the director of the Observatory between 1938-1943, and Gheorghe Demetrescu (director between 1943-1963), decided to partially dismantle and keep in a safe place some of the scientific instruments.
The scientific activity of the Observatory restarted at new levels in 1945 under the same academic coordination of the University of Bucharest.
Between 1951-1975, the institutional leadership of the Astronomical Observatory was transferred from the University of Bucharest to the Romanian Academy. During this period, the two directors of the Astronomical Observatory, Gheorghe Demetrescu and Constantin Drâmbă, together with the teams they coordinated, managed to overcome countless financial and institutional difficulties and to advance with the Romanian astronomical research. Their scientific interest was driven by two directions: fundamental astronomy and astrophysics. The topics covered were: meridian astronomy, astrophotography, Sun observations, monitoring of the Earth’s artificial satellites, precise determination of astronomical time, Earth’s rotation studies.
The Bucharest Observatory participated in the International Geophysical Year to a vast multi-national effort for studying the Earth with the most modern scientific means. For this participation and for other scientific purposes, several modern Zeiss telescopes and Belin quartz clocks were installed. In 1956, the eastern side of the main building of the Observatory was expanded. Inside the extension added to the initial construction the Time and Frequency Laboratory was organized. The Romanian Academy also constructed two new specialized buildings: the Sun Dome (1958) and the Telescope Dome (1962). The Time Department participated in the MERIT international campaign (Monitoring of the Earth Rotation and Inter-comparison of the Techniques and Methods), whose results led to the replacement of the classic ground-based techniques with modern space ones.
In 1961, as the total solar eclipse of February 15 wasn’t visible from the ground due to the clouds, the astronomers of the Observatory managed to take five photos of the eclipse from a military plane.
A strong recognition of the merits and research capacity of the Observatory’s astronomers and the importance of their work was given in 1974, when the Romanian Academy awarded the prize “Gheorghe Lazăr” to the team of specialists coordinated by Ella Marcus for their work “Bucharest KSZ Catalogue of Faint Stars for 1950.0”.
A new change in the institutional management of the Astronomical Observatory took place in 1975 when it was transferred under the authority of the Central Physics Institute, as a division of the Astronomy and Space Sciences Center.
On the 1st of April 1990, the Astronomical Observatory returns under the authority of the Romanian Academy and its name changed to the current one: the Astronomical Institute. This was also the moment when the three astronomical observatories in Bucharest, Cluj-Napoca and Timişoara, were included in the same institution.
Under the leadership of Magda Stavinschi, the director of the Astronomical Institute between 1990-2005, the patrimony of buildings comprising its scientific park was restored and developed. The intensive restoration included the consolidation of the Sun Building from its basement up to the tower, a complete restoration of the Small Meridian Hall based on its surviving foundation and the transformation of the ruined Bosianu House through restoration and modernization to an astronomy library. In 1999, a Planetarium Building was added to the northern side of the main building. This was the work of the architect Octav Dimitriu and of the civil engineer Radu Popescu. A new generation of scientific equipment was purchased and operated.
A very important event was the total solar eclipse on the 11th of August 1999, whose maximum was in Romania. On this occasion, at the Observatory high guests such as the President of Romania, the General Manager of NASA, scientists, diplomats, cultural personalities and media were welcomed. The live transmission from Romania was broadcasted all over the globe, while the event gave the Astronomical Institute the opportunity to start a fund-raising campaign for its further development and modernization.
After 1990, the main fields of scientific research of the Astronomical Institute are: the physics and evolution of the stars, the physics of the Sun, the dynamics of celestial bodies in the Solar system, celestial mechanics, cosmology, the history of astronomy and astronomical education.
In more than a century of research, the Astronomical Institute edited and promoted several scientific publications: “Studies and Researches of Astronomy ans Seismology”, “Studies and Researches of Astronomy”, “Romanian Astronomical Journal” and “Astronomical Yearbook”.
The Astronomical Observatory in the 1920’s
Team of scientists and workers during the installation of the Gautier-Prin telescope in the Meridian Hall (1926)