C. Donald Shane 3m Reflector Telescope
Traditional telescopes are refractor telescopes, using optics to bend distant light sources to allow it to be visualized by eye. The problem, as alluded to by the problems besetting the Great Lick Telescope, was that larger and larger optics were needed to see more distant objects, creating a danger of the glass cracking and introducing chromatic aberrations. A reflector telescope on the other hand, uses curved mirrors to collect and focus light for the image to form, which allows only one side to be polished and the other supported as well as the use of smaller optical pieces. The C. Donald Shane telescope was erected on Mount Hamilton in 1959, after the observatory's refractor telescopes had long become outdated. It has an 120 inch aperture. It remains the fifth-largest reflector telescope in the world and remains in active use.
Mount Hamilton, San Jose, California