The first four attempts to cast the mirror were unsuccessful. The fifth attempt, using a different technique, created a blank (somewhat larger than originally intended). Three years of grinding and polishing followed. When installed in the telescope mount in 1931, it was the third largest mirror in the world. (Prior to installation of the mirror, the observatory used a mirror on loan from Harvard University.) OSU era Early on it became apparent that the Ohio Wesleyan University simply did not have the staff or expertise necessary to operate one of the world's most important observatories. In 1935 a cooperative agreement was reached with the Ohio State University in Columbus, Ohio to staff and operate Perkins Observatory. For the next 63 years, for most practical purposes, the observatory belonged to OSU. The following three decades were Golden Years for Perkins Observatory. The remote skies were dark (if somewhat cloudy). Famous astronomers from around the world traveled to central Ohio to use the large telescope. Important meetings of professional and amateur astronomers were hosted on site. The library collection grew to include many rare volumes. Astronomer Philip C. Keenan spent most of his professional life as an astronomer working at Perkins Observatory. (He was employed by the Ohio State University, not Ohio Wesleyan.) Using the telescope he spent almost 20 years taking spectrographic plates of vast areas of the night sky. In collaboration with William Wilson Morgan of Yerkes Observatory, Dr. Keenan helped to create the M-K System of Stellar Classification. (“M” is for Morgan and “K” is for Keenan.) This is the most common stellar classification system used by astronomers today. In 1932 the Acting Director of the Observatory Nikolai T. Bobrovnikov began publication of a small in-house magazine known as “The Telescope.” At first this quarterly dealt primarily with research and current events related to Perkins Observatory, but in following issues it expanded its coverage of topics somewhat. In 1941 it merged with another small astronomy magazine known as “The Sky” to create “Sky & Telescope Magazine.” Another stipulation in Hiram Perkins’ endowment was that observing sessions be open to the public at least once a month. The radio telescope known as Big Ear was built on Perkins Observatory property and operated from 1963 to 1998. It was famous in part for its work on SETI and the WOW! Signal detected in 1977. This instrument was built and operated by