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Workmen washing the 200-inch telescope mirror on the floor of the dome, Palomar Observatory. Color photograph. Four unidentified men, three standing on a platform and one perched in a chute above the center of the mirror, clean the mirror. Portions of the 200-inch telescope are seen above them. Image courtesy of the Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, California.