A two-ton 84-inch telescope mirror, manufactured for the Kitt Peak National Observatory, Tuscon, Arizona, USA, was recently completed at the New York Corning Glass Works.
LV. Lens out of oven
SV. Chipping away plaster
SV. Man inspects lens
LV. Lens in crate
LV. Crate on to lorry
GV. Crate into train truck
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Background: A two-ton 84-inch telescope mirror, manufactured for the Kitt Peak National Observatory, Tuscon, Arizona, USA, was recently completed at the New York Corning Glass Works.
The giant lens was taken from a sealed oven where it had spent seven months following melt-down. Nine pieces of glass, one weighing 2,976 lbs were sagged under intense heat to form the 13-inch thick disc. A centre core, 26 inches in diameter, enables a man to crawl through for check-ups. After a detailed inspection, the mirror was packed in a specially-built, felt-lined crate for its rail journey across country to Arizona.
At Arizona City it was taken to an optical firm for final grinding and polishing. A process taking two years before the lens can be finally mounted on the telescope. Another year of precision finishing will follow.
The telescope mirror will be used by the Observatory to photograph light from stars billions of light years away.
It is the fourth largest telescope mirror produced in America, and the largest made in the past 25 years.