100 Hours of Astronomy is the single largest event taking place during IYA2009. It is a worldwide celebration composed of a broad range of activities aimed at involving the public. The event will take place over four days and nights, from 2-5 April 2009 (local time). During this period, people from around the globe will share the experience of observing the sky. For many, it will be their first glimpse of the wonders of the heavens through a telescope. For others, it is the perfect opportunity to impart their knowledge and excitement, helping unveil the cosmos to fresh and eager eyes.

100 Hours of Astronomy is a venture of breathtaking scope that seeks to involve people from all walks of life around the globe and conveys a multitude of messages, from the personal benefit of astronomical knowledge to the pressing issue of curbing light pollution. Clear your agenda now for 100 hours of discovery!
Related links:
:: 100 Hours of Astronomy in Paris [.pdf]
:: 100 Hours of Astronomy (around the world)
:: Order a "Galileoscope"
:: UNESCO International Year of Astronomy 2009 (More)
:: Le Rallye parisien, Friday 03 April (More) [only in French]
:: 100 Hours update (More)
:: International Year of Astronomy 2009