Royal Observatory, Greenwich | observatory | Royal Observatory | Paris Observatory | Palomar Observatory | Yerkes Observatory | Arecibo Observatory | Siding Spring Observatory | Mount Wilson Observatory | Smithsonian Astrophysical Observatory | Observatory | Harvard College Observatory | Ondřejov Observatory | Lowell Observatory | Kew Observatory | Roque de los Muchachos Observatory | Pulkovo Observatory | McDonald Observatory | Jodrell Bank Observatory | Chandra X-ray Observatory | Solar Dynamics Observatory | National Astronomical Observatory of Japan | Las Campanas Observatory | European Southern Observatory | Allegheny Observatory | Vienna Observatory | United States Naval Observatory | Parkes Observatory | Observatory, Cape Town | National Radio Astronomy Observatory |
OFO should not to be confused with similar acronyms describing the Orbiting Observatory series of spacecraft, such as Orbiting Geophysical Observatory (OGO), Orbiting Solar Observatory (OSO), and Orbiting Astronomical Observatory (OAO).