... Star Party on Planet Earth . ... As twilight sweeps around planet Earth tonight (April 4), many amateur astronomers will set up their telescopes for a 24-hour global star party. The planetwide star party is part of 100 Hours of Astronomy (100HA), a project of the International Year of Astronomy 2009. ... The 24-hour long webcast is organized by the European Southern Observatory for the International Year of Astronomy cornerstone project 100 Hours of Astronomy. 100 Hours of Astronomy Begins . ...