This is the telescope that completely changed our perception of the size of the universe. Although it had been theorized for many years....as far back as 1864, it wasn't until 1929 and publication of Edwin Hubble's work that the majority of astronomers finally believed that our Milky Way was only one of hundreds of billions of galaxies stretched outward to apparent infinity. Up until that time, the debate raged.......the "nebulae" as the galaxies were called then, were "Island Universes" outside the Milky Way, or, as some believed, clouds of gas in our galaxy. It's quite a story.
The Hooker 100 inch reflector on Mt. Wilson near Pasadena, CA. First light: 1917