For information on using Huntington Library materials, please see Reproductions of Huntington Library Holdings: https://www.huntington.org/library-rights-permissions
Progress on construction of the new wing of Mount Wilson Observatory's Office Building (as seen from roof of government building), Pasadena. The new wing under construction is seen to the right of the main office building. Rooftops of other buildings in the surrounding area are also seen in the foreground. Image courtesy of the Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, California.