The Allegheny Observatory is an American astronomical research institution, a part of the Department of Physics and Astronomy at the University of Pittsburgh. The facility is listed on the National Register of Historical Places (ref. # 79002157, added 6-22-1979) and is designated as a Pennsylvania state and Pittsburgh History and Landmarks Foundation historic landmark.
The observatory was founded on February 15, 1859, in the city of Allegheny, Pennsylvania (incorporated into the city of Pittsburgh in 1907) by a group of wealthy industrialists calling themselves the Allegheny Telescope Association. The observatory's initial purpose was for general public education as opposed to research, but by 1867 the revenues derived from this had receded. The facility was then donated to the Western University of Pennsylvania, today's University of Pittsburgh.
The University hired Samuel Pierpont Langley to be the first director. One of the research programs initiated under his leadership was of sunspots. He drew very detailed drawings of sunspots which are still used in astronomical textbooks to this day. He also had the building expanded to include dark rooms, class rooms, dormatories, and a lecture hall.
On November 18, 1883, the first day of railroad standard time in North America, the Allegheny Observatory transmitted a signal on telegraph lines operated by railroads in Canada and the United States. The signal marked noon, Eastern Standard Time, and railroads across the continent synchronized their schedules based on this signal. The standard time that began on this day continues in North American use to this day.
The revenues from the sale of time signals covered Langley's salary and the bills. Allegheny Observatory continued to supply time signals until the US Naval Observatory started offering it for free in 1920.
A unique event occurred while Langley was the director. After arriving home from a conference, observatory staff came to his home in Allegheny City and told him his presence was needed immediately at the observatory. Upon arriving at the observatory he discovered the lens had been stolen for ransom. Langley refused to pay the ransom, and arguments ensued between Langley and the lensnapper. It is suspected Langley knew who the lensnapper was, although his or her identity is still a mystery to this day. Meanwhile the newspapers were investigating who could be the lensnapper, and feeling his identity may be discovered, told Langley he could have the lens. It was never returned by the lensnapper, and was eventually found in a wastepaper basket in a hotel in Beaver Falls, Pennsylvania. The lens had a bad scratch in it, making it useless. The lens was sent off to a lens maker to be reground. In the end it turns out the lensnapping was a gift in disguise for after the regrinding the lens was ten times better than before!
Langley also did research into heavier than air flight behind the observatory. He had a large spring arm to which stuffed birds and wings he made were attached, and he would study how wings worked. After leaving Allegheny Observatory to become secretary of the Smithsonian in 1888, he continued his heavier than air research. He eventually was launching test planes off of boats in the Potomac River, and he was being funded by the United States Congress. A well publicized and exaggerated crash had Congress pull the funding, ending Langley's research.
The original observatory building was replaced by the current structure, shown in the photograph above. It was designed in the Classic Revival style by T.E. Billquist. The cornerstone was laid in 1900, and the new structure was completed in 1912. It is located four miles north of downtown Pittsburgh, Pennsylvania at Riverview Park. The building is a tan brick and white terra cotta hilltop temple whose Classical forms and decoration symbolize the unity of art and science. The L-shaped building consists of a library, lecture hall, classrooms, laboratories, offices and three hemispherical domed telescope enclosures. Two were reserved for research; one for use by schools and the general public. The core of the building is a small rotunda, housing an opalescent glass window depicting the Greek muse of astronomy, Urania. A crypt in the observatory holds the ashes of two eminent astronomers and former directors of the Allegheny Observatory, James Edward Keeler and John Brashear.
Among other research purposes, the observatory presently searches for extrasolar planets. This is done using astrometry, which is the practice of measuring the position of stars. The position of a target star and its close neighbors are measured using the Multichannel Astrometric Photometer (MAP). Measurements are taken twice a year, 6 months apart. This technique takes advantage of parallax. If the target star has a companion then it will wobble due to the gravitational pull of the unseen companion. The size of the companion can be measured by the size of the wobble.
The observatory has thousands of photographic plates in its vaults, and the stars on those plates are also being measured for the extrasolaor planet work.