Telescope centennial

The 60-inch telescope at Mount Wilson Observatory in southern California turns 100 this month.

A celebration of the telescope’s centennial in November featured appearances by Sam Hale, grandson of George Ellery Hale, who founded Mount Wilson Observatory and commissioned the telescope, and Todd and Robin Mason, producers of the PBS television documentary Journey to Palomar, about Hale and his quest to build the biggest telescopes of his time; the documentary premiered on 10 November.

Probably the most notable accomplishment with the telescope was Harlow Shapley’s 1917 measurement of the size of the Milky Way and his discovery that the Sun is not at the galaxy’s center. “The 60-inch continued the Copernican Revolution by dethroning the Sun from the center of our galaxy,” says observatory director Harold McAlister.

When the telescope was built, it was the largest in the world. It was retired from active science in the mid-1990s and is now the largest telescope devoted to public outreach.