Foto de stock - 1961 - 20 Ton Telescope Mirror Worth Quarter Of A Million Arrives For Polishing In Newcastle: The largest piece of glass ever imported into the United Kingdom, a 20 ton telescope Mirror, has arrived at the Grubb Parsone Works at Newcastle Upon Tyne for an eighteen month grinding and polishing operation. The new 155.5 inch mirror made of a zero-expansion glass-ceramic material called 'Cer---- Vit' developed by Owens Illinois U.S.A. was cast in Toledo, Ohio, in April this year. It will be installed in a telescope being jointly developed by the British Science Research Council and Australian Department of Education and Science at Siding Spring Mountain, New South Wales. Photo shows A general view looking down on the Mirror Blank before grinding and Polishing starts at the Grubb Parsons Works at Newcastle today. (Credit Image: © Keystone Pictures USA/ZUMAPRESS.com)