The international year of astronomy is jointly sponsored by the International Astronomical Union (IAU) and the United Nations Educational, Scientific and Cultural Organization (UNESCO) with the theme of "Exploring Our Universe". To commemorate the 400th anniversary of Galileo's first astronomical observation with a telescope, on February 20th, 2007, the United Nations passed a resolution to designate 2009 as the international year of astronomy.

International year of astronomy 2009 is first and foremost an important global event. Its purpose is to convey the joy of personal discovery and spread the joy of sharing scientific knowledge. Astronomical spirit is a valuable resource for all nationalities in the world.

The slogan of international year of astronomy in 2009 is "Exploring the Universe". The symbol of international year of astronomy in 2009 is a photo of two people looking up at the starry sky hand in hand.