The International Astronomical Union (IAU) was founded in 1919. Its mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. Its individual members — structured into Divisions, Commissions, and Working Groups — are professional astronomers from all over the world, at the Ph.D. level and beyond, who are active in professional research and education in astronomy. The IAU has 12527 members. The Individual Members Directory contains 10004 names in 101 countries worldwide (These Individual Members are labeled as "active" in the IAU database: they have a valid, public email, and are affiliated to at least one Division.). Of those 79 are National Members. In addition, the IAU collaborates with various scientific organizations all over the world.
The long-term policy of the IAU is defined by the General Assembly and implemented by the Executive Committee, while day-to-day operations are directed by the IAU Officers. The focal point of its activities is the IAU Secretariat, hosted by the Institut d'Astrophysique de Paris, France. The scientific and educational activities of the IAU are organized by its 9 Scientific Divisions and, through them, its 35 specialized Commissions covering the full spectrum of astronomy, along with its 54 Working Groups.
The key activity of the IAU is the organization of scientific meetings. Every year the IAU sponsors nine international IAU Symposia. The IAU Symposium Proceedings series is the flagship of the IAU publications. Every three years the IAU holds a General Assembly, which offers six IAU Symposia, some 25 Joint Discussions and Special Sessions, and individual business and scientific meetings of Divisions, Commissions, and Working Groups. The proceedings of Joint Discussions and Special Sessions are published in the Highlights of Astronomy series. The reports of the GA business meetings are published in the Transactions of the IAU - B series.
Among the other tasks of the IAU are the definition of fundamental astronomical and physical constants; unambiguous astronomical nomenclature; promotion of educational activities in astronomy; and informal discussions on the possibilities for future international large-scale facilities. Furthermore, the IAU serves as the internationally recognized authority for assigning designations to celestial bodies and surface features on them.
The IAU also works to promote astronomical education, research and public outreach actions towards the public. These activities culminated with the organization of the UNESCO International Year of Astronomy in 2009, which reached out to over 800 million people from 148 countries. Following this effort, the IAU created the Office of Astronomy for Development (OAD), a joint venture with the South African National Research Foundation as well as with the IAU Office for Astronomy Outreach (OAO), a joint venture with the National Astronomical Observatory of Japan. Astronomy is used as a tool for stimulating capacity building by means of 3 IAU OAD Task Forces - Universities and Research, Children and Schools and Public Outreach. Regional offices have been created in other countries as well. In 2015 actively participated in the International Year of Light. The IAU also carries out joint educational activities associated with COSPAR and UNESCO.
