Warren Rupp Observatory, south of Mansfield, Ohio, is operated by the Richland Astronomical Society and houses one of the world’s largest amateur-operated telescopes. Its origins trace to a 1968 donation of a 31-inch mirror blank, originally intended for the McMath Solar Observatory on Kitt Peak, Arizona. After about 2,000 hours of grinding, the telescope saw first light in 1974 and was given to the society in 1982 on condition that a building be built for it. Financed chiefly by Warren Rupp and completed in 1985, the observatory later replaced its shattered original mirror in 2011 and now supports public observing, education, outreach, and the Hidden Hollow star party.