Allegheny Observatory is one of the major astronomical research institutions in the United States and the world. The large Neo-classical structure is located in Riverview Park, four miles north of the Golden Triangle in downtown Pittsburgh, and eight miles from the University of Pittsburgh, of which it is a part. Allegheny Observatory’s origin dates to 1859, when a group of like-minded citizens — originally three and later 29 — formed the Allegheny Telescope Association, out of the curiosity to observe stars and other astronomical phenomena. When they solicited funds to purchase an eight-inch telescope to be mounted on a roof, the public response was overwhelming. It was that unexpected response that virtually changed the destiny of what might have remained a modest stargazing club. Soon, the association was reorganized as the Allegheny Observatory Society. A building, equipped with a 13-inch telescope, was constructed on a hill overlooking Perrysville Avenue and the Federal Street extension. In due course, the hill came to be known as Observatory Hill and, between 1890 and 1908, also became the campus of the Western University of Pennsylvania — now the University of Pittsburgh. Eventually, the observatory was acquired by the university as an adjunct to its astronomy department. The present building at Riverview Park was constructed in 1912, a long 12 years after its cornerstone had been laid. It was designed by architect Thorsten E. Billquist, and built large enough to accommodate future developments in astronomy and equipment. When the building was completed, the observatory was equipped with three telescopes, all of which are still in continual use. The Allegheny Observatory building resembles a basilica — a large rectangular block with two semi-circular rooms surmounted by two small domes flanking the entranceway, and a long hallway leading to a larger dome set at the opposite end. The three domes and circular sections — designed to hold the telescopes — dominate the façade and layout of the observatory. The first floor contains a lecture hall, laboratories, guest rooms and a technical library. Throughout its history, the Allegheny Observatory has been a nerve center of research and development. It was here that Professor Samuel P. Langley made the first heavier-than-air airplane model and successfully tested a pilotless model in sustained flight. Other famous contributions by the observatory include the "Allegheny Time System," the spectroscopic research of Saturn’s rings, and various inventions of high-precision astrometry. Today, the observatory effectively combines the latest technology and data of the past by pursuing new discoveries while maintaining its reputation as an astronomical research pioneer. To educate the public in the basics of astronomy and space, the observatory offers weekly tours. In addition, there is a special open house held once a year — usually early fall — when all the three telescopes are available for public viewing.