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Devendra Pratap Singh

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Palomar telescope

In 1936, a glass casting for the first 200-inch diameter, reflecting telescope mirror was shipped by train from Corning, New York to California for the new Hale telescope at the Mt. Palomar Observatory. It was cast on 2 Dec 1934, put in an annealing oven, then slowly allowed to cool for a year. The mirror weighed 20 tons, and was made of Pyrex glass, which does not expand and contract as much during temperature changes as ordinary glass. The train took about two weeks to reach Pasadena, travelling at a speed always under 25 m.p.h. to keep the mirror, in its specially made crate, safe from shocks. Upon arrival, the crate was taken to the optical workshop at the California Institute of Technology to begin a four-year grinding process to shape and polish the mirror. Work was delayed by WW II, and the Hale telescope in its new observatory building was dedicated on 3 Jun 1948.«Image: With the same size and weight as the 200 inch mirror, this cement disk was used while the telescope was built to test the mount.

What do you call a p...

“What do you call a piano built in Miami? The Florida Keys.”

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