September 20, 2006

The 26^th General Assembly of the International Astronomical Union (IAU) took place in the Congress Center Prague, from 14^th to 25^th August 2006. Our capital welcomed the astronomers from all over the world again after 39 years, since the 13^th IAU General Assembly was held also in Prague in 1967.

The Prague General Assembly was held under the auspices of the President of the Czech Republic Václav Klaus, former President of the Czech Republic Václav Havel, President of the Academy of Sciences of the Czech Republic Václav Pačes, Lord Mayor of the Capital of Prague Pavel Bém and the Rectors of the Charles University in Prague, Czech Technical University in Prague and Masaryk University in Brno.

The last IAU General Assembly took place in Sydney, the next ones are being prepared for 2009 in Rio de Janeiro and 2012 in Beijing.

Prague welcomed the astronomers from 73 countries who came to discuss and evaluate the most recent discoveries and observations, to go through fundamental scientific, technical and administrative problems and to agree on future international cooperation. The topics covered all astronomical disciplines, ranging from our closest neighborhood to the farthest objects of the universe.

In total, 2412 astronomers participated at the General Assembly, out of which there were 540 students and 115 seniors (the latter two categories paying substantially lower registration fee). Early registration fee, lowered by about 25 per cent, was used by about 85 per cent of participants, 87 persons registered on site. There were 208 registered guests, including 38 children younger than 11 years.

The participants could use the internet connection in Internet Room in which both desktop computers and tens of free connections for laptop computers were installed. About 1 TB of data was transmitted via this fixed network. Thanks to a sponsorship of T-Mobile CZ almost unlimited wireless connection was made possible for those who brought their laptops equipped with WIFI cards. In total, 18370 of wireless connections to internet were used that lasted 15500 hours; about 250 GB of data were transmitted during the whole General Assembly. This corresponds to approximately 1800 fifty-minute connections each day.

The program of the General Assembly consisted of 6 symposia (3.5-day long), 17 Joint Discussions (1-2 day long), 7 Special Sessions (1-2 day long), the debates of Young Astronomers and Women in Astronomy, and about 110 business meetings of Divisions, Commissions and Working Groups of the IAU. During the scientific program almost 650 oral papers were presented and more than 1550 posters displayed. There were also four Invited Discourses of the leading world astronomers: Jill Tarter (The evolution of life in the Universe), Alan Title (The magnetic field and its effects on the solar atmosphere as observed at high resolution), Shuang Nan Zhang (Similar phenomena at different scales: Black holes, sun, supernovae, galaxies and galactic clusters) and Reinhard Genzel (The power of new experimental techniques in astronomy: Zooming in on the black hole in the center of the Milky Way). Three presentations of leading astronomers were also made for the Czech public at the building of the Academy of Sciences that were interpreted into Czech (Jill Tarter, Francoise Combes and Reinhard Genzel).

The IAU General Assembly touched a major part of actual questions of astronomy, astrophysics and related disciplines. Among others, small bodies of the Solar System that could closely approach the Earth, double stars and their role in determining the distances in the Universe, star formation, evolution of galaxies, black holes, and new definition of a planet in the Solar System were discussed.

A rich accompanying program was prepared for the participants that more than 2200 persons utilized. Except for tours to the most interesting parts of our country they could take part in the excursion to the Ondřejov Observatory, and a historical colloquium „Astronomical Prague“ was organized.

An exhibition was set up in the Congress Center Prague in which 34 companies and institutions from the whole world participated. From the Czech Republic these were: Astronomical Institute of the Academy of Sciences, Kleť Observatory, Czech Space Office, Czech Astronomical Society, T-Mobile CZ and Academia publishing house. Among exhibitors, there was also the Virtual Observatory Alliance.

Every workday a newspaper „Dissertatio cum Nuncio Sidereo III“ was issued that provided a symbolic link to the astronomical past of the Czech Lands when Johannes Kepler published in Prague his work Dissertatio cum Nuncio Sidereo in 1610, and when the newspaper „Dissertatio cum Nuncio Sidereo II“ was issued during the Prague IAU General Assembly in 1967.

The IAU General Assembly was not open for public. However, some parts were transmitted live to the internet by web-streaming, thanks to a sponsorship provided by MediaStream company. All sessions that took place in the Congress Hall were transmitted: Opening and Closing Ceremonies, all four Invited Discourses, discussions and voting on the new definition of a planet and the talk by the laureate of Gruber Foundation Prize, J. Mather. More than 8 thousand spectators followed these transmissions during the General Assembly. The most popular was the voting on planet definition during the second plenary session which about 5 thousand spectators witnessed in real time. All these transmissions are recorded and are accessible through the internet, by September 18 more than 21 thousand accesses were recorded.

The introductory Press Conference for Czech journalists took place in the building of the Academy of Sciences in Prague, before the opening of the General Assembly, on August 10. Daily press conferences took place during the meetings, directly in the Congress Center, in which both officers of the IAU and important world astronomers participated. The General Assembly was mostly covered by the stations of the Czech Radio (Radiožurnál, Praha, Vltava, Leonardo, ČRo 6), but also by the Czech press and Czech TV which provided service to many TV companies in abroad. There were 125 domestic and 70 international journalists and press agencies accredited. The eye-witnesses of IAU General Assemblies agreed that this Prague General Assembly had the highest publicity in the history.

Several Czech astronomers were honored during the assembly. Kamil Hornoch obtained a prize of the Pacific Astronomical Society for 2006 for astronomers - amateurs, Zdenĕk Sekanina got the Nušl prize of the Czech Astronomical Society for his whole-life scientific work, the IAU Symposium 240 (Double stars) was dedicated to Miroslav Plavec and the editor of the international scientific journal „Solar Physics“ organized a festive lunch as a tribute to Zdenĕk Švestka. The congress newspaper remembered in a long article the outstanding Czech astrophysicist František Link whose 100th birthday fell on the second congress day.

The following Czech astronomers were elected to important high positions in the IAU for the next three years:

J. Vondrák – President of Division I (Fundamental Astronomy)
P. Spurný – President of Commission 22 (Meteors, Meteorites and Interplanetary Dust)
J. Tichá – Chair of the Division III Committee on Small Bodies Nomenclature
C. Ron – member of the Financial Subcommittee of the IAU