After 39 years the International Astronomical Union (IAU) returns to Prague and it is my great pleasure to invite you to attend this 26th General Assembly (GA) which will be taking place from August 14 to 25, 2006. Thirty nine years is only a brief moment in Prague's great astronomical history which reaches back more than 400 years to Tycho Brahe and Johannes Kepler and the era of the Copernican revolution, but it's half the lifetime of the IAU. if you look at the reproductions of stories in the 1967 International Astronomical Union General Assembly newspaper Dissertatio cum Nuncio Sidereo II on the General Assembly web site you can appreciate the extraordinary developments that have occurred in astronomy over this short period.
Following the now established pattern we will have an extensive scientific programme of Symposia, Joint Discussions and six Special Sessions as well as four Invited Discourses, on essentially all topics of contemporary astronomy. New features in the Prague General Assembly will be the "hot topics" sessions to capture the excitement of the most recent astronomical activities, and a number of lunch meetings to debate topics of social and cultural importance.
There are now a plethora of astronomical meetings, mostly with international participation, but the IAU General Assemblies are unique in offering not only a large variety of specialised scientific meetings but also the freedom to attend meetings in other fields to gain new perspectives on our science. The General Assembly will also give you the opportunity to meet with astronomers and colleagues from around the world to discuss common interests, to organise cooperative ventures and to renew old friendships.
The IAU was founded in 1919 by the International Research Council, (now ICSU). Its mission "to promote and safeguard the science of astronomy in all its aspects through international cooperation" is little changed since 1919. The language of science binds IAU members, strengthened by a shared vision to better understand the universe and a love of astronomy. This transcends where you were born and to where you migrate. A few years after the last Prague General Assembly at the IAU 50th anniversary, J H Dort said: "Looking over the entire time of my relations with the Union the most important aspects have been in the first place the many personal relations and often friendships which came about through these relations, and, in the second place, having become involved in building up international understanding and fertile contact between countries where sometimes relations outside astronomy were extremely poor. Politicians have rightly envied us for the natural ties between peoples we have been able to establish and conserve." Sadly Dort's comment on relations between countries remains as true today as it was forty years ago but I am greatly heartened by the success of the IAU groups working on education and development world wide as well as the IAU's role in promoting international collaborations.
The IAU depends totally on the contributions (mostly unpaid) of the many people in the Executive, the Divisions, the Commissions and in the Working Groups which are the foundation of all our work. I wish to thank all my IAU colleagues, and in particular the General Secretary, Oddbjørn Engvold, the Assistant General Secretary, Karel van der Hucht, and our secretarial staff in the Paris Office, Monique Orine who maintains the IAU corporate memory and Claire Vidonne who has designed and brought to fruition much of the new IAU membership data base and website. An IAU General Assembly makes particularly onerous demands on the astronomers in the host country. We owe a great debt to Jan Palouas and the rest of his team who have invited us to share their historical Prague for this General Assembly of astronomers.
Ron Ekers, IAU President