the 19th century List of the largest optical telescopes in North America References External links Cincinnati Observatory Center View The Cincinnati Observatory Center in 3D Cincinnati Observatory Center Clear Sky Clock Forecasts of observing conditions. Merz und Mahler telescope photos 1843 establishments in Ohio Astronomical observatories in Ohio National Historic Landmarks in Ohio Planetaria in the United States Tourist attractions in Cincinnati Education in Cincinnati Buildings and structures in Cincinnati National Register of Historic Places in Cincinnati Research institutes established in 1843