Mount Wilson Observatory, high in the San Gabriel Mountains near Pasadena, became one of the most important centers in modern astronomy because its steady mountain air favored precise observation. Founded through George Ellery Hale’s efforts and first funded in 1904 by the Carnegie Institution of Washington, it emerged as a leader in solar physics through instruments such as the Snow Solar Telescope and the sixty-foot and one hundred fifty-foot Solar Towers. Its nighttime telescopes, especially the sixty-inch reflector and the one hundred-inch Hooker telescope, enabled landmark discoveries including evidence of magnetic fields beyond Earth, Andromeda’s distance beyond the Milky Way, and the expansion of the universe. It remains an active research and historic site.

Photo: Wikipedia · Public domain

Photo: Wikipedia · Public domain

Photo: Wikipedia · Public domain

Photo: Wikipedia · Public domain

Altadena, California · USA