Mount Palomar telescope eyepiece. This is the eyepiece section of the 200-inch (5-meter) Hale Telescope, built from 1936 and operational from 1948. It is named after the astronomer George Ellery Hale, who proposed it and oversaw the installation. This telescope was the world's largest of its type until 1976. Many important advances in astronomy were made with this instrument, such as the first observation of a brown dwarf star and the first optical spectrum obtained from a quasar. It is part of the Mount Palomar Observatory, located at an elevation of 1867 meters in the Palomar mountains, California, USA.