Perched atop California’s Mount Wilson, the 100-inch reflecting telescope took “first light” on the night of Nov. 1, 1917. The name “100-inch” isn’t the size of the entire telescope.

The 100-inch telescope mirror is transported to Mt. Wilson Observatory in July 1917. (Courtesy of the Observatories of the Carnegie Institution for Science Collection at the Huntington Library) ...

Hale quickly got to work building an even bigger telescope on Mount Wilson than he’d had back in Wisconsin, and in December 1908, a new 60-inch telescope was used for the first time, dwarfing ...

In the 1920s, Edwin Hubble was working with the 100-inch Hooker telescope on Mount Wilson, just outside Los Angeles. At the time, it was the largest telescope in the world. On a chilly evening, I ...

Tom Meneghini, executive director of the Mount Wilson Institute, is photographed Sept. 23 next to the 100-inch Hooker telescope located at the Mount Wilson Observatory in Los Angeles.

Mount Wilson Observatory is a Los Angeles-area facility with several telescopes open to astronomers and the public. Several notable discoveries have been made using the observatory's telescopes.

One of Mount Wilson’s Interferometric Array telescopes in the foreground with the 60-inch telescope in the background on August 3, 2007, which has been instrumental in the modern understanding ...

It's been a century since the Mount Wilson Observatory arose almost 6,000 feet above Pasadena. ... and environmental changes made its original 60-inch telescope a relic.

At about that time, Ritchey was designing the 100-inch Hooker Telescope at Mount Wilson, which he and the observatory’s director, George Ellery Hale, assumed would employ a paraboloidal primary ...

Designed by George Ellery Hale, the Hooker telescope at Mount Wilson Observatory used a 100-inch diameter mirror, making it the largest telescope in the world at the time.