The world's largest fully steerable radio telescope, with an elliptically shaped dish, 100 × 110 m, opened in 2000 at the National Radio Astronomy Observatory site in Green Bank, West Virginia. It has an actively controlled surface to maintain its shape, and features an off-axis secondary held by an arm outside the dish so that the telescope's aperture is not obstructed. Its full title is the Robert C. Byrd Green Bank Telescope.
http://www.gb.nrao.edu/GBT/GBT.shtml Official telescope website.
Subjects: Astronomy and Astrophysics.