observations from the 100 inch telescope at Mount Wilson, demonstrated that the nebulae were in fact huge galaxies unimaginably far from our own. This discovery revolutionized our understanding of the size of the universe.
In the 1940s and 1950s photo- graphic sky surveys taken with telescopes at Lick Observatory and Palomar Mountain provided the first solid evidence that clusters of galaxies gathered into larger groups. In the 1950s astronomer Gerard de Vaucouleurs, working at the University of Texas, used extensive observations of the Virgo Cluster and the Local Group to describe the Local Supercluster. The case for superclusters was further advanced by the observations and cataloguing of clusters by Fritz Zwicky and
