Abstract

The 2018 General Assembly in Vienna is the best opportunity to mark the Centenary of the Union. Although the IAU was founded in July 1919, August 2018 will be the perfect time for this unique opportunity, as so many astronomers will be in Vienna at that time, and a large number will be interested in attending this Centenary Symposium to celebrate this significant milestone. A separate symposium in July 2019 would not have attracted the same interest or have had the same impact. Although celebrating the IAU centenary is one aspect of the proposed symposium, it is emphasized that this is far from the major rationale for the proposed symposium. The history of astronomy is a major scientific discipline in its own right, which is recognized by the IAU through commission C.C3. However, the symposium will be only the second ever IAU symposium where the history of astronomy is a major focus (the first was IAU Symposium 269 in January 2010 on Galileo’s Medicean moons). This symposium will be a major scientific meeting on the history of astronomy and astrophysics over the last 100 years; the celebration of the IAU’s success over this time will be one significant aspect but not the main focus. On the other hand, the IAU Centenary Committee will organize an evening event to celebrate the centenary of the IAU at the time of this symposium.