Edwin Hubble remained on the staff of Mount Wilson Observatory until 1953, the year he died. He first joined the observatory in 1919, shortly after returning from military service and completing his astronomy training.
Mount Wilson was then home to the 100-inch Hooker Telescope, the world’s largest operating telescope. Hubble used it to resolve individual stars in spiral nebulae, including Cepheid variables whose known luminosities allowed astronomers to estimate distances. This work showed that many nebulae were separate galaxies beyond the Milky Way.
Hubble temporarily left active observatory work during World War II, when he contributed to military research. He returned afterward and continued working with Mount Wilson and the developing Palomar Observatory project. The wording “until 1953” refers to his institutional association, not uninterrupted observing every year.
Hubble died on September 28, 1953, in San Marino, California. His death ended a career closely associated with Mount Wilson, although the observatory’s scientific legacy continued through later generations of astronomers.