The United Nations Has declared 2009 the International Year of Astronomy (IYA2009). IYA2009 is an initiative of the International Astronomical Union (IAU) and UNESCO, the United Nations Education, Science and Culture organisation. The UN resolution was proposed by Italy, the country where Galileo Galilei made the first astronomical observations through a telescope 400 years ago.

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 invention of the astronomical telescope took place in the Netherlands the year before and is celebrated throughout 2008. The aim of IYA2009 is to stimulate worldwide interest, especially among young people, in astronomy and science under the central theme "The Universe, Yours to Discover". 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 first astronomical observations with a telescope in 1609 unleashed a scientific revolution that has profoundly changed our perception of the universe and our place in it. 400 years later, modern telescopes on Earth and in space explore the universe in all wavelengths. Astronomy is a science that drives collaborations across all boundaries: geographical, cultural, racial, gender and age, in line with the vision of the United Nations. Astronomy is a formidable example of how science can contribute to international cooperation worldwide.

A National Working groups has been established in the Netherlands to prepare for the IYA2009 activities for education and public outreach in order to reach as many people as possible. Internationally over 100 countries are taking part in the global celebration of IYA2009, as well as 14 international organisations.