English: United States President Barack Obama looks through a telescope during an Astronomy Night event on the South Lawn of the White House on Wednesday, 7 October 2009. The President and First Lady, Michelle Obama , hosted the star party to mark the International Year of Astronomy (IYA2009), which celebrated the 400th anniversary of Galileo Galilei 's first use of a telescope. The President addressed a group of 150 local school students, and astronauts Buzz Aldrin , Mae Jemison , John Grunsfeld , and Sally Ride also attended. The President's science advisor John Holdren guided the President in viewing a double star in the constellation Lyra through an 8" diffraction limited Schmidt–Cassegrain telescope .