ASME-Landmark:Mount Wilson Observatory, 100-Inch Hooker Telescope

The Mount Wilson Observatory was founded in 1904 by the Carnegie Institution of Washington, a private foundation for scientific research supported largely from endowments provided by Andrew Carnegie. Within a few years, the Observatory became the world center of research in the new science of astrophysics, or the application of principles of physics to astronomical objects beyond the sun.

In 1902, George Ellery Hale proposed and persuaded the Carnegie Institution that an observatory be started in the California wilderness above Pasadena. The first facilities to be built were the 60-foot and 150-foot solar towers and the 60-inch reflector. Hale began planning the 100-inch telescope project as early as 1906, and its design and construction took place from 1910-1918. Major engineering problems solved during its construction included supporting the massive mirror with no final stress that would distort its surface in any positions. Among its noteworthy features is the use of mercury flotation for reduction of friction.

The Mount Wilson 100-inch reflector dominated discoveries in astronomy from its beginning in 1918 until the dedication of the Palomar 200-inch reflector in 1948. One of its most important results was the 1924 discovery that the total light output of the stars could be found by inspection of the record made when starlight is dispersed into a spectrum by a prism or grating. Coupled with the 1930 observation that velocities of galaxies increase progressively with ever-increasing distances, the Mount Wilson reflector helped answer the most basic question of cosmology—what is the nature of the large scale structure of the Universe. See ASME website for more information