The International Year of Astronomy 2009 (IYA2009) is a global initiative celebrating astronomy's societal and cultural contributions, commemorating Galileo Galilei's first astronomical telescope use. With the theme "The Universe, Yours to Discover," IYA2009 aims to ignite interest in astronomy and science worldwide, particularly among youth. This event features activities promoting the inspirational aspects of astronomy and serves as a valuable shared resource for nations globally.

From national to local levels, IYA2009 activities are organized by National Nodes across 148 countries, fostering collaborations among astronomers, educators, and science communicators. The initiative boasts 40 Organisational Nodes, 33 Organisational Associates, and 111 National Websites. With 12 Cornerstone Projects, 11 Special Task Groups, and 16 Special Projects, IYA2009 offers a range of engaging activities.

Official Products, media partnerships, and global sponsors bolster this astronomy celebration endorsed by the United Nations and the International Council of Science