The Sky at Night — Episode 11: The Mount Wilson Observatory

You are watching the episode The Mount Wilson Observatory In 1917 astronomy entered a new era. The great 100-inch reflecting telescope on Mount Wilson in California was completed. It was far more powerful than any existing telescope, and it soon led to the discovery that we live in an expanding universe. Mount Wilson Observatory is still in full use. Patrick Moore visits the observatory and talks to some of the astronomers who are working there.