The International Year of Astronomy (IYA2009) will be a global celebration of astronomy and its contributions to society and culture, highlighted by the 400th anniversary of the first use of an astronomical telescope by Galileo Galilei. The aim of the Year is to stimulate worldwide interest, especially among young people, in astronomy and science. IYA2009 events and activities will promote a greater appreciation of the inspirational aspects of astronomy that embody an invaluable shared resource for all nations.

The IYA2009 activities will take place locally, regionally and nationally. National Nodes in each country have
been formed to prepare activities for 2009. These Nodes establish collaborations between professional and amateur astronomers, science centers and science communicators in preparing activities for 2009. More than 90 countries are already involved, with well over 140 expected. To help coordinate this huge global program, and to provide an important resource for the participating countries, the IAU has established a central Secretariat and this website as the principal IYA resource for public, professionals, and media alike.