National Radio Astronomy Observatory
The National Radio Astronomy Observatory is a Federally Funded Research and Development Center of the United States National Science Foundation operated under cooperative agreement by Associated Universities, Inc for the purpose of radio astronomy. NRAO designs and operates its own high sensitivity radio telescopes for use by scientists around the world; the NRAO headquarters is located on the campus of the University of Virginia in Charlottesville, Virginia. The North American ALMA Science Center and the NRAO Technology Center and Central Development Laboratory are located in Charlottesville, Virginia. NRAO was, until October 2016, the operator of the world's largest steerable radio telescope, the Robert C. Byrd Green Bank Telescope, which stands near Green Bank, West Virginia; the observatory contains several other telescopes, among them the 140-foot telescope that utilizes an equatorial mount uncommon for radio telescopes, three 85-foot telescopes forming the Green Bank Interferometer, a 40-foot telescope used by school groups and organizations for small scale research, a fixed radio'horn' built to observe the radio source Cassiopeia A, as well as a reproduction of the original antenna built by Karl Jansky while he worked for Bell Labs to detect the interference, discovered to be unknown natural radio waves emitted by the universe.
Green Bank is in the United States National Radio Quiet Zone, coordinated by NRAO for protection of the Green Bank site as well as the Sugar Grove, West Virginia monitoring site operated by the NSA. The zone consists of a 13,000-square-mile piece of land where fixed transmitters must coordinate their emissions before a license is granted; the land was set aside by the Federal Communications Commission in 1958. No fixed radio transmitters are allowed within the area closest to the telescope. All other fixed radio transmitters including TV and radio towers inside the zone are required to transmit such that interference at the antennas is minimized by methods including limited power and using directional antennas. With the advent of wireless technology and microprocessors in everything from cameras to cars, it is difficult to keep the sites free of radio interference. To aid in limiting outside interference, the area surrounding the Green Bank observatory was at one time planted with pines characterized by needles of a certain length to block electromagnetic interference at the wavelengths used by the observatory.
At one point, the observatory faced the problem of North American flying squirrels tagged with US Fish & Wildlife Service telemetry transmitters. Electric fences, electric blankets, faulty automobile electronics, other radio wave emitters have caused great trouble for the astronomers in Green Bank. All vehicles on the premises are powered by diesel motors to minimize interference by ignition systems; the NRAO's facility in Socorro is the Pete V. Domenici Array Operations Center. Located on the New Mexico Tech university campus, the AOC serves as the headquarters for the Very Large Array, the setting for the 1997 movie Contact, is the control center for the Very Long Baseline Array; the ten VLBA telescopes are located in Hawaii, the U. S. Virgin Islands, eight other sites across the continental United States. Offices are located on the University of Arizona campus. NRAO operated the 12 Meter Telescope on Kitt Peak. NRAO suspended operations at this telescope and funding was rerouted to the Atacama Large Millimeter Array instead.
The Arizona Radio Observatory now operates the 12 Meter Telescope. The Atacama Large Millimeter Array site in Chile is at ~5000 m altitude near Cerro Chajnantor in northern Chile; this is about 40 km east of the historic village of San Pedro de Atacama, 130 km southeast of the mining town of Calama, about 275 km east-northeast of the coastal port of Antofagasta. The Karl G. Jansky Lectureship is a prestigious Lecture awarded by the Board of Trustees of the NRAO; the Lectureship is awarded "to recognize outstanding contributions to the advancement of radio astronomy." Recipients have included Fred Hoyle, Charles Townes, Edward M. Purcell, Subrahmanyan Chandrasekhar, Philip Morrison, Vera Rubin, Jocelyn Bell Burnell, Frank J. Low and Mark Reid; the lecture is delivered in Socorro. Official website
USS Albany (CA-123)
USS Albany was a United States Navy Oregon City-class heavy cruiser converted to the guided missile cruiser CG-10. The converted cruiser was the lead ship of the new Albany guided missile cruiser class, she was the fourth ship to carry the name Albany. The ship was laid down on 6 March 1944 at Quincy, Massachusetts, by the Bethlehem Steel Company, launched on 30 June 1945, sponsored by Mrs. Elizabeth F. Pinckney, commissioned on 15 June 1946 at the Boston Navy Yard, Captain Harold A. Carlisle in command. Following outfitting and a shakedown cruise in the vicinity of Casco Bay, Albany began operations along the east coast of the United States punctuated with cruises to the West Indies. During the ensuing months, the cruiser made a number of voyages for the purpose of training naval reservists and NROTC midshipmen. Albany continued to perform such duty until 11 September 1948, when she stood out of Chesapeake Bay for her first tour of duty with the American naval forces operating in the Mediterranean Sea made a permanent establishment as the 6th Fleet.
That deployment set the tone for the next decade. The cruiser alternated five assignments to the 6th Fleet with operations along the east coast of the United States and in the West Indies and made three cruises to South American ports. During one of the South American voyages, Albany carried the official United States representative to the inauguration of the President of Brazil in January 1951. For two years, stretching at least until the autumn of 1955, Albany served as flagship for Commander, Battleship-Cruiser Force, Atlantic. On 30 June 1958, Albany was placed out of commission at the Boston Naval Shipyard to begin conversion to a guided missile cruiser. On 1 November 1958, she was redesignated CG-10; the warship spent the next four years at Boston undergoing extensive modifications as part of the conversion. Albany was recommissioned at Boston on 3 November 1962 with Captain Ben B. Pickett in command. For five years, she alternated deployments to European waters – both to the Mediterranean Sea and to the North Atlantic – with operations along the east coast and in the West Indies.
During that time, the cruiser visited many foreign ports and participated in a number of exercises with units of friendly navies. On 1 March 1967, she was decommissioned at the Boston Naval Shipyard once again to undergo extensive modifications; some 20 months on 9 November 1968, Albany was placed back in commission at Boston with Captain Allan P. Slaff in command. In 1973, the ship was again decommissioned for overhaul at the Philadelphia Naval Shipyard, it was recommissioned in May 1974 and homeported in Norfolk, VA under the command of Captain John J. Ekelund. Shortly thereafter it became the flagship of the 2nd Fleet. Between 1976 and 1980, Albany was the flagship of the 6th Fleet, homeported in Gaeta, Italy. Albany was decommissioned on 29 August 1980 and laid up on the Elizabeth River across from the Norfolk Navy Yard, she was stricken from the Naval Vessel Register on 30 June 1985 but she remained at her berth and held for possible donation as a museum ship in her name sake city for a further 5 years.
Though there was serious interest in saving the ship, a feasible museum and financial plan was never realized and she was sold for scrapping on 12 August 1990. A portion of Albany's bow resides at the Albany County Fairgrounds in New York; the original 14-foot-long brass model of the ship built by the United States Navy to help determine where antenna arrays would go on the actual-size ships was restored in 2013 and is on display at the Albany Heritage Area Visitors Center. Albany. USS Albany CA-123: Mediterranean Cruise of 1951.:, 1951. OCLC 30880411 Albany; the USS Albany: 1955 Mediterranean Cruise.:, 1955. OCLC 30881092 USS Albany Association homepage Photos of Albany Naval Vessel Register entry for Albany Entry for Ekelund RangeThis article includes information collected from the public domain sources Dictionary of American Naval Fighting Ships and Naval Vessel Register
Cornell University is a private and statutory Ivy League research university in Ithaca, New York. Founded in 1865 by Ezra Cornell and Andrew Dickson White, the university was intended to teach and make contributions in all fields of knowledge—from the classics to the sciences, from the theoretical to the applied; these ideals, unconventional for the time, are captured in Cornell's founding principle, a popular 1868 Ezra Cornell quotation: "I would found an institution where any person can find instruction in any study."The university is broadly organized into seven undergraduate colleges and seven graduate divisions at its main Ithaca campus, with each college and division defining its own admission standards and academic programs in near autonomy. The university administers two satellite medical campuses, one in New York City and one in Education City and Cornell Tech, a graduate program that incorporates technology and creative thinking; the program moved from Google's Chelsea Building in New York City to its permanent campus on Roosevelt Island in September 2017.
Cornell is one of ten private land grant universities in the United States and the only one in New York. Of its seven undergraduate colleges, three are state-supported statutory or contract colleges through the State University of New York system, including its agricultural and human ecology colleges as well as its industrial labor relations school. Of Cornell's graduate schools, only the veterinary college is state-supported; as a land grant college, Cornell operates a cooperative extension outreach program in every county of New York and receives annual funding from the State of New York for certain educational missions. The Cornell University Ithaca Campus comprises 745 acres, but is much larger when the Cornell Botanic Gardens and the numerous university-owned lands in New York City are considered; as of October 2018, 58 Nobel laureates, four Turing Award winners and one Fields Medalist have been affiliated with Cornell University. Since its founding, Cornell has been a co-educational, non-sectarian institution where admission has not been restricted by religion or race.
Cornell counts more than 245,000 living alumni, its former and present faculty and alumni include 34 Marshall Scholars, 30 Rhodes Scholars, 29 Truman Scholars, 7 Gates Scholars, 55 Olympic Medalists, 14 living billionaires. The student body consists of more than 14,000 undergraduate and 8,000 graduate students from all 50 American states and 116 countries. Cornell University was founded on April 27, 1865. Senator Ezra Cornell offered his farm in Ithaca, New York, as a site and $500,000 of his personal fortune as an initial endowment. Fellow senator and educator Andrew Dickson White agreed to be the first president. During the next three years, White oversaw the construction of the first two buildings and traveled to attract students and faculty; the university was inaugurated on October 7, 1868, 412 men were enrolled the next day. Cornell developed as a technologically innovative institution, applying its research to its own campus and to outreach efforts. For example, in 1883 it was one of the first university campuses to use electricity from a water-powered dynamo to light the grounds.
Since 1894, Cornell fulfill statutory requirements. Cornell has had active alumni since its earliest classes, it was one of the first universities to include alumni-elected representatives on its Board of Trustees. Cornell was among the Ivies that had heightened student activism during the 1960s related to cultural issues, civil rights, opposition to the Vietnam War. Today the university has more than 4,000 courses. Cornell is known for the Residential Club Fire of 1967, a fire in the Residential Club building that killed eight students and one professor. Since 2000, Cornell has been expanding its international programs. In 2004, the university opened the Weill Cornell Medical College in Qatar, it has partnerships with institutions in India and the People's Republic of China. Former president Jeffrey S. Lehman described the university, with its high international profile, a "transnational university". On March 9, 2004, Cornell and Stanford University laid the cornerstone for a new'Bridging the Rift Center' to be built and jointly operated for education on the Israel–Jordan border.
Cornell's main campus is on East Hill in Ithaca, New York, overlooking Cayuga Lake. Since the university was founded, it has expanded to about 2,300 acres, encompassing both the hill and much of the surrounding areas. Central Campus has laboratories, administrative buildings, all of the campus' academic buildings, athletic facilities and museums. North Campus is composed of ten residence halls that house first-year students, although the Townhouse Community houses transfer students; the five main residence halls on West Campus make up the West Campus House System, along with several Gothic-style buildings, referred to as "the Gothics". Collegetown contains two upper-level residence halls and the Schwartz Performing Arts Center amid a mixed-use neighborhood of apartments and businesses; the main campus is marked by an irregular layout and eclectic architectural styles, including ornate Collegiate Gothic and Neoclassical buildings, the more spare international and modernist structures. The more ornat
Norwood is the second most populous city in Hamilton County, United States, an enclave of the larger city of Cincinnati. The population was 19,207 at the 2010 census. Settled as an early suburb of Cincinnati in the wooded countryside north of the city, the area is characterized by older homes and tree-lined streets; the earliest humans in the area now known as Norwood are believed to have been Pre-Columbian era people of the Adena culture. Norwood Mound, a prehistoric earthwork mound built by the Adena, is located in Norwood and listed on the National Register of Historic Places; the Adena constructed the mound at the location of Norwood's present-day Water Tower Park, the highest land elevation in the city and one of the highest in all of Hamilton County. Archaeologists believe the mound was built at this site due to the high elevation and was used by the Adena for religious ceremonies and smoke signaling. Native American mounds are not uncommon in Ohio and several were located in Downtown Cincinnati at the time of arrival of the first white settlers.
However, by 1895, the Norwood Mound was the only remaining mound in the vicinity of Cincinnati." The mound has never been excavated, but it is reported that many artifacts found in the area by early Norwood settlers in the 1800s made up the original nucleus of the Native American Art Collection of the Cincinnati Art Museum. In the early-20th century, Norwood High School named their sports team mascot the Indians in honor of this local Native American heritage. In 1787, the United States Congress established the Northwest Territory, John Cleves Symmes, Congressman from New Jersey, purchased 311,682 acres of the territory, within which the future Norwood is located. One year the first permanent settlement on the banks of the Ohio River in what would become Cincinnati was established. In 1793, General "Mad Anthony" Wayne led several companies of troops from Fort Washington in Cincinnati to advance against a hostile tribe of Native Americans encamped on the banks of the nearby Millcreek in what is now St. Bernard.
Historians believe that a company of troops under the direction of General Wayne made their way through Norwood during this campaign and widened an old Native American trail, which followed the path of present-day Smith Road, Montgomery Road, Carthage Avenue. In 1859, an early Norwood pioneer named Joseph G. Langdon claimed to have found a bullet buried in the heart of an oak tree on his Norwood property left by Anthony Wayne's troops 66 years earlier. In 1794, a pioneer named Peter Smith settled on Duck Creek in or near the current location of Norwood, it is believed. Soon after, a road was built connecting the early settlement of Columbia on the Ohio River near the Little Miami River with the settlement of Carthage, just north of Cincinnati; this road cut through Norwood along the old Indian Path widened by General Wayne's troops. Anthony Wayne's victory over the Indians at the Battle of Fallen Timbers the same year signaled the end of the Northwest Indian War which enabled pioneers to begin settling former hostile lands such as the future Norwood.
In 1795, another road was built along the present-day path of Montgomery Road, connecting Cincinnati with Montgomery and beyond. Montgomery Road was known as the "State Road" and Smith Road/Carthage Avenue was known as the "County Road."In 1809, a settler named Samuel D. Bowman purchased land near the crossing of the State Road and the County Road, where he established a tavern and coach stop for travelers, he was soon joined by John Sharp, who built a cabin and small country store at the opposite side of the intersection. The community of half a dozen houses soon became known after Mr. Sharp. For the next half century, the little coach stop along the road between Cincinnati and Columbus didn't create much of a stir in the world. In 1866, the first tracks of the Marietta and Cincinnati Railroad were completed, connecting Loveland with Cincinnati; the tracks ran from east to west through Sharpsburg and still exist in the same location today, parallel to the Norwood Lateral Expressway and passing under the Montgomery Road overpass.
The village did not have a train station when the railway opened, but the possibility of passenger rail access to Cincinnati generated interest in developing a residential subdivision nearby. In 1868, two early developments were platted in the area north of the railroad, the Joseph G. Langdon Subdivision at Sharpsburg on the east side of Montgomery Road, the Baker Addition to Sharpsburg on the west; the first train station was opened on Langdon's Sharpsburg development in 1868. In 1869, Sylvester H. Parvin, Col. Philander P. Lane and Lemuel Bolles purchased the William Ferguson farm north of the Marietta and Cincinnati Railroad tracks and platted an eighty-one-acre subdivision they called Norwood Heights; this was the first recorded use of the name Norwood in the area. It is believed that the person who came up with the name was Sarah Bolles, wife of Lemuel Bolles. In the 1894 book, Her Homes and Her People, it was stated that the name "Sharpsburg" was "not considered pretty enough for such a spot, the suggestion of Mr. and Mrs. Bolles to call it Norwood met with endorsement, so it was that the suburb was christened anew."However, the origin of the name Norwood is disputed.
It is stated that Mrs. Bolles's name for the 1869 Norwood Heights subdivision was inspired by Henry Ward Beecher's popular 1869 novel Norwood: or, Village Life in New England. Others have claimed Mrs. Bolles arrived at the name by combining "North Woods", in reference to Norwood being a wood
University of California, Santa Cruz
The University of California, Santa Cruz is a public research university in Santa Cruz, California. It is one of 10 campuses in the University of California system. Located 75 miles south of San Francisco at the edge of the coastal community of Santa Cruz, the campus lies on 2,001 acres of rolling, forested hills overlooking the Pacific Ocean and Monterey Bay. Founded in 1965, UC Santa Cruz began as a showcase for progressive, cross-disciplinary undergraduate education, innovative teaching methods and contemporary architecture. While still retaining its reputation for strong undergraduate support and student political activism, it has since evolved into a modern research university with a wide variety of both undergraduate and graduate programs; the residential college system, which consists of ten small colleges, is intended to combine the student support of a small college with the resources of a major university. Although some of the original founders had outlined plans for an institution like UCSC as early as the 1930s, the opportunity to realize their vision did not present itself until the City of Santa Cruz made a bid to the University of California Regents in the mid-1950s to build a campus just outside town, in the foothills of the Santa Cruz Mountains.
The Santa Cruz site was selected over a competing proposal to build the campus closer to the population center of San Jose. Santa Cruz was selected for the beauty, rather than the practicality, of its location and its remoteness led to the decision to develop a residential college system that would house most of the students on-campus; the formal design process of the Santa Cruz campus began in the late 1950s, culminating in the Long Range Development Plan of 1963. Construction had started by 1964, the university was able to accommodate its first students in 1965; the campus was intended to be a showcase for contemporary architecture, progressive teaching methods, undergraduate research. According to founding chancellor Dean McHenry, the purpose of the distributed college system was to combine the benefits of a major research university with the intimacy of a smaller college. UC President Clark Kerr shared a passion with former Stanford roommate McHenry to build a university modeled as "several Swarthmores" in close proximity to each other.
Roads on campus were named after UC Regents. Although the city of Santa Cruz exhibited a strong conservation ethic before the founding of the university, the coincidental rise of the counterculture of the 1960s with the university's establishment fundamentally altered its subsequent development. Early student and faculty activism at UCSC pioneered an approach to environmentalism that impacted the industrial development of the surrounding area; the lowering of the voting age to 18 in 1971 led to the emergence of a powerful student-voting bloc. A large and growing population of politically liberal UCSC alumni changed the electorate of the town from predominantly Republican to markedly left-leaning voting against expansion measures on the part of both town and gown. Plans for increasing enrollment to 19,500 students and adding 1,500 faculty and staff by 2020, the anticipated environmental impacts of such action, encountered opposition from the city, the local community, the student body. City voters in 2006 passed two measures calling on UCSC to pay for the impacts of campus growth.
A Santa Cruz Superior Court judge invalidated the measures, ruling they were improperly put on the ballot. In 2008, the university, city and neighborhood organizations reached an agreement to set aside numerous lawsuits and allow the expansion to occur. UCSC agreed to local government scrutiny of its north campus expansion plans, to provide housing for 67 percent of the additional students on campus, to pay municipal development and water fees. George Blumenthal, UCSC's 10th Chancellor, intends to mitigate growth constraints in Santa Cruz by developing off-campus sites in Silicon Valley; the NASA Ames Research Center campus is planned to hold 2,000 UCSC students – about 10% of the entire university's future student body as envisioned for 2020. In April 2010, UC Santa Cruz opened its new $35 million Digital Arts Research Center; the $72 million Coastal Biology Building opened on 21 October 2017 on the Coastal Science Campus. The new campus houses the Ecology & Evolutionary Biology Department and faculty interested in the study of ocean and freshwater environments, marine sciences and evolution, plant sciences.
UC Santa Cruz is extending its environmental leadership in coastal science with a robust new program that will welcome its first cohort of students in Fall 2018. The Graduate Program in Coastal Science and Policy will train advocates and develop government and community responses to pressing sustainability issues; the 2,000-acre UCSC campus is located 75 miles south of San Francisco, in the Ben Lomond Mountain ridge of the Santa Cruz Mountains. Elevation varies from 285 feet at the campus entrance to 1,195 feet at the northern boundary, a difference of about 900 feet; the southern portion of the campus consists of a large, open meadow, locally known as the Great Meadow. To the north of the meadow lie most of the campus' buildings, many of them among redwood groves; the campus is bounded on the south by the city's upper-west-side neighborhoods, on the east by Harvey West Park and the Pogonip open space preserve, on the north by Henry Cowell Redwoods State Park near the town of Felton, on the west by Gray
Illinois is a state in the Midwestern and Great Lakes region of the United States. It has the fifth largest gross domestic product, the sixth largest population, the 25th largest land area of all U. S. states. Illinois is noted as a microcosm of the entire United States. With Chicago in northeastern Illinois, small industrial cities and immense agricultural productivity in the north and center of the state, natural resources such as coal and petroleum in the south, Illinois has a diverse economic base, is a major transportation hub. Chicagoland, Chicago's metropolitan area, encompasses over 65% of the state's population; the Port of Chicago connects the state to international ports via two main routes: from the Great Lakes, via the Saint Lawrence Seaway, to the Atlantic Ocean and from the Great Lakes to the Mississippi River, via the Illinois Waterway to the Illinois River. The Mississippi River, the Ohio River, the Wabash River form parts of the boundaries of Illinois. For decades, Chicago's O'Hare International Airport has been ranked as one of the world's busiest airports.
Illinois has long had a reputation as a bellwether both in social and cultural terms and, through the 1980s, in politics. The capital of Illinois is Springfield, located in the central part of the state. Although today's Illinois' largest population center is in its northeast, the state's European population grew first in the west as the French settled the vast Mississippi of the Illinois Country of New France. Following the American Revolutionary War, American settlers began arriving from Kentucky in the 1780s via the Ohio River, the population grew from south to north. In 1818, Illinois achieved statehood. Following increased commercial activity in the Great Lakes after the construction of the Erie Canal, Chicago was founded in the 1830s on the banks of the Chicago River at one of the few natural harbors on the southern section of Lake Michigan. John Deere's invention of the self-scouring steel plow turned Illinois's rich prairie into some of the world's most productive and valuable farmland, attracting immigrant farmers from Germany and Sweden.
The Illinois and Michigan Canal made transportation between the Great Lakes and the Mississippi River valley faster and cheaper, new railroads carried immigrants to new homes in the country's west and shipped commodity crops to the nation's east. The state became a transportation hub for the nation. By 1900, the growth of industrial jobs in the northern cities and coal mining in the central and southern areas attracted immigrants from Eastern and Southern Europe. Illinois was an important manufacturing center during both world wars; the Great Migration from the South established a large community of African Americans in the state, including Chicago, who founded the city's famous jazz and blues cultures. Chicago, the center of the Chicago Metropolitan Area, is now recognized as a global alpha-level city. Three U. S. presidents have been elected while living in Illinois: Abraham Lincoln, Ulysses S. Grant, Barack Obama. Additionally, Ronald Reagan, whose political career was based in California, was born and raised in the state.
Today, Illinois honors Lincoln with its official state slogan Land of Lincoln, displayed on its license plates since 1954. The state is the site of the Abraham Lincoln Presidential Library and Museum in Springfield and the future home of the Barack Obama Presidential Center in Chicago. "Illinois" is the modern spelling for the early French Catholic missionaries and explorers' name for the Illinois Native Americans, a name, spelled in many different ways in the early records. American scholars thought the name "Illinois" meant "man" or "men" in the Miami-Illinois language, with the original iliniwek transformed via French into Illinois; this etymology is not supported by the Illinois language, as the word for "man" is ireniwa, plural of "man" is ireniwaki. The name Illiniwek has been said to mean "tribe of superior men", a false etymology; the name "Illinois" derives from the Miami-Illinois verb irenwe·wa - "he speaks the regular way". This was taken into the Ojibwe language in the Ottawa dialect, modified into ilinwe·.
The French borrowed these forms, changing the /we/ ending to spell it as -ois, a transliteration for its pronunciation in French of that time. The current spelling form, began to appear in the early 1670s, when French colonists had settled in the western area; the Illinois's name for themselves, as attested in all three of the French missionary-period dictionaries of Illinois, was Inoka, of unknown meaning and unrelated to the other terms. American Indians of successive cultures lived along the waterways of the Illinois area for thousands of years before the arrival of Europeans; the Koster Site demonstrates 7,000 years of continuous habitation. Cahokia, the largest regional chiefdom and urban center of the Pre-Columbian Mississippian culture, was located near present-day Collinsville, Illinois, they built an urban complex of more than 100 platform and burial mounds, a 50-acre plaza larger than 35 football fields, a woodhenge of sacred cedar, all in a planned design expressing the culture's cosmology.
Monks Mound, the center of the site, is the largest Pre-Columbian structure north of the Valley of Mexico. It is 100 feet high, 951 feet long, 836 feet wide, covers 13.8 acres. It contains about 814,000 cubic yards of earth, it was topped by a structure thought to have measured about 105 feet in length and 48 feet in width, covered an area 5,000 square feet, been as much as 50 feet high, making its peak 150 feet above the level of the pl
The Arecibo Observatory is a radio telescope in the municipality of Arecibo, Puerto Rico. This observatory is operated by University of Central Florida, Yang Enterprises and UMET, under cooperative agreement with the US National Science Foundation; the observatory is the sole facility of the National Astronomy and Ionosphere Center, the formal name of the observatory. From its construction in the 1960s until 2011, the observatory was managed by Cornell University. For more than 50 years, from its completion in 1963 until July 2016 when the Five hundred meter Aperture Spherical Telescope in China was completed, the Arecibo Observatory's 1,000-foot radio telescope was the world's largest single-aperture telescope, it is used in three major areas of research: radio astronomy, atmospheric science, radar astronomy. Scientists who want to use the observatory submit proposals that are evaluated by an independent scientific board; the observatory has appeared in film and television productions, gaining more recognition in 1999 when it began to collect data for the SETI@home project.
It has been listed on the US National Register of Historic Places starting in 2008. It was the featured listing in the US National Park Service's weekly list of October 3, 2008; the center was named an IEEE Milestone in 2001. It has a visitor center, open part-time. On September 21, 2017, high winds associated with Hurricane Maria caused the 430 MHz line feed to break and fall onto the primary dish, damaging about 30 out of 38,000 aluminum panels. Most Arecibo observations do not use the line feed but instead rely on the feeds and receivers located in the dome. Overall, the damage inflicted by Maria was minimal; the main collecting dish is 305 m in diameter, constructed inside the depression left by a karst sinkhole. The dish surface is made of 38,778 perforated aluminum panels, each about 3 by 6 feet, supported by a mesh of steel cables; the ground beneath supports shade-tolerant vegetation. The observatory has four radar transmitters, with effective isotropic radiated powers of 20 TW at 2380 MHz, 2.5 TW at 430 MHz, 300 MW at 47 MHz, 6 MW at 8 MHz.
The reflector is a spherical reflector, not a parabolic reflector. To aim the device, the receiver is moved to intercept signals reflected from different directions by the spherical dish surface of 270 m radius. A parabolic mirror would have varying astigmatism when the receiver is off the focal point, but the error of a spherical mirror is uniform in every direction; the receiver is on a 900-ton platform suspended 150 m above the dish by 18 cables running from three reinforced concrete towers, one 111 m high and the other two 81 m high, placing their tops at the same elevation. The platform has a rotating, bow-shaped track 93 m long, called the azimuth arm, carrying the receiving antennas and secondary and tertiary reflectors; this allows the telescope to observe any region of the sky in a forty-degree cone of visibility about the local zenith. Puerto Rico's location near the Northern Tropic allows Arecibo to view the planets in the Solar System over the Northern half of their orbit; the round trip light time to objects beyond Saturn is longer than the 2.6 hour time that the telescope can track a celestial position, preventing radar observations of more distant objects.
The origins of the observatory trace to late 1950s efforts to develop anti-ballistic missile defences as part of the newly formed ARPA's ABM umbrella-effort, Project Defender. At this early stage it was clear that the use of radar decoys would be a serious problem at the long ranges needed to attack a warhead, ranges on the order of 1,000 miles. Among the many Defender projects were several studies based on the concept that a re-entering nuclear warhead would cause unique physical signatures while still in the upper atmosphere, it was known that hot, high-speed objects caused ionization of the atmosphere that reflects radar waves, it appeared that a warhead's signature would be different enough from decoys that a detector could pick out the warhead directly, or alternately, provide added information that would allow operators to focus a conventional tracking radar on the single return from the warhead. Although the concept appeared to offer a solution to the tracking problem, there was no information on either the physics of re-entry or a strong understanding of the normal composition of the upper layers of the ionosphere.
ARPA began to address both simultaneously. To better understand the radar returns from a warhead, several radars were built on Kwajalein Atoll, while Arecibo started with the dual purpose of understanding the ionosphere's F-layer while producing a general-purpose scientific radio observatory; the observatory was built between mid-1960 and November 1963. William E. Gordon of Cornell University oversaw its design, who intended to use it to study the Earth's ionosphere, he was attracted to the sinkholes in the karst regions of Puerto Rico that offered perfect cavities for a large dish. A fixed parabolic reflector was envisioned, pointing in a fixed direction with a 150 m tower to hold equipment at the focus; this design would have limited its use in other research areas, such as radar astronomy, radio astronomy and atmospheric science, which require the ability to point at different positions in the sky and track those positions for an extended time as Earth rotates. Ward Low of the Advanced Research Projects Agency pointed out this flaw and put Gordon in touch with the Air Force Cambridge Research Laboratory in Boston, where one group headed by Phil Blacksmith was working