Arecibo Observatory

Arecibo Observatory

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The Arecibo Observatory is a radio telescope
Radio telescope
A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...

 near the city of Arecibo
Arecibo, Puerto Rico
Arecibo is a municipality in the northern midwest coast of Puerto Rico and located by the Atlantic Ocean, north of Utuado and Ciales; east of Hatillo; and west of Barceloneta, and Florida. Arecibo is spread over 18 wards and Arecibo Pueblo...

 in Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...

. It is operated by SRI International
SRI International
SRI International , founded as Stanford Research Institute, is one of the world's largest contract research institutes. Based in Menlo Park, California, the trustees of Stanford University established it in 1946 as a center of innovation to support economic development in the region. It was later...

 under cooperative agreement with the National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...

. The observatory
Observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...

 is also called the National Astronomy and Ionosphere Center, although "NAIC" refers to both the observatory and the staff that operate it.

The observatory's 305 m (1,000.7 ft) radio telescope
Radio telescope
A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...

 is the largest single-aperture telescope (cf.
Cf.
cf., an abbreviation for the Latin word confer , literally meaning "bring together", is used to refer to other material or ideas which may provide similar or different information or arguments. It is mainly used in scholarly contexts, such as in academic or legal texts...

 multiple aperture telescope
Aperture synthesis
Aperture synthesis or synthesis imaging is a type of interferometry that mixes signals from a collection of telescopes to produce images having the same angular resolution as an instrument the size of the entire collection...

) ever constructed. It carries out three major areas of research: radio astronomy
Radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...

, aeronomy
Aeronomy
Aeronomy is the science of the upper region of the atmosphere, where dissociation and ionization are important. The term aeronomy was introduced by Sydney Chapman, and the above definition stems from 1960. Today the term also includes the science of the corresponding regions of the atmospheres of...

 (using both the 305 m telescope and the observatory's lidar
LIDAR
LIDAR is an optical remote sensing technology that can measure the distance to, or other properties of a target by illuminating the target with light, often using pulses from a laser...

 facility), and radar astronomy
Radar astronomy
Radar astronomy is a technique of observing nearby astronomical objects by reflecting microwaves off target objects and analyzing the echoes. This research has been conducted for six decades. Radar astronomy differs from radio astronomy in that the latter is a passive observation and the former an...

 observations of solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...

 objects. Scientists who want to use the telescope submit proposals, which are evaluated by an independent board.

Visually distinctive, the telescope makes frequent appearances in motion picture and television productions. The telescope received additional international recognition in 1999 when it began to collect data for the SETI@home
SETI@home
SETI@home is an Internet-based public volunteer computing project employing the BOINC software platform, hosted by the Space Sciences Laboratory, at the University of California, Berkeley, in the United States. SETI is an acronym for the Search for Extra-Terrestrial Intelligence...

 project.

The center was listed on the U.S. National Register of Historic Places
National Register of Historic Places
The National Register of Historic Places is the United States government's official list of districts, sites, buildings, structures, and objects deemed worthy of preservation...

 in 2008. It was the featured listing in the National Park Service
National Park Service
The National Park Service is the U.S. federal agency that manages all national parks, many national monuments, and other conservation and historical properties with various title designations...

's weekly list of October 3, 2008. The center was named an IEEE Milestone in 2001.

Ángel Ramos Foundation Visitor Center


Opened in 1997, the Ángel Ramos Foundation Visitor Center features interactive exhibits and displays about the operations of the radio telescope, astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

, and atmospheric science
Atmospheric sciences
Atmospheric sciences is an umbrella term for the study of the atmosphere, its processes, the effects other systems have on the atmosphere, and the effects of the atmosphere on these other systems. Meteorology includes atmospheric chemistry and atmospheric physics with a major focus on weather...

. The center is named after the foundation created by Ángel Ramos
Angel Ramos (industrialist)
Angel Ramos was the founder of Telemundo, the second largest Spanish-language television network in the United States.-Early years:...

, the founder of Telemundo
Telemundo
Telemundo is an American television network that broadcasts in Spanish. The network is the second-largest Spanish-language content producer in the world, and the second-largest Spanish-language network in the United States, behind Univision....

, which provided half of the money to build it, with the rest coming from private donations and Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

. The admission fee is $10.

General information


The main collecting dish is 305 m (1,000.7 ft) in diameter, constructed inside the depression left by a karst
KARST
Kilometer-square Area Radio Synthesis Telescope is a Chinese telescope project to which FAST is a forerunner. KARST is a set of large spherical reflectors on karst landforms, which are bowlshaped limestone sinkholes named after the Kras region in Slovenia and Northern Italy. It will consist of...

 sinkhole
Sinkhole
A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the Earth's surface caused by karst processes — the chemical dissolution of carbonate rocks or suffosion processes for example in sandstone...

. It contains the largest curved focusing dish on Earth, giving Arecibo the largest electromagnetic-wave-gathering capacity. The dish surface is made of 38,778 perforated aluminum panels, each measuring about 3 by, supported by a mesh of steel cables.

The telescope has three radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

 transmitters, with effective isotropic radiated powers of 20 TW at 2380 MHz, 2.5 TW (pulse peak) at 430 MHz, and 300 MW at 47 MHz.

The telescope is a spherical reflector, not a parabolic reflector
Parabolic reflector
A parabolic reflector is a reflective device used to collect or project energy such as light, sound, or radio waves. Its shape is that of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis...

. To aim the telescope, the receiver is moved to intercept signals reflected from different directions by the spherical dish surface. A parabolic mirror would induce a varying astigmatism
Astigmatism
An optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances...

 when the receiver is in different positions off the focal point, but the error of a spherical mirror
Spherical aberration
thumb|right|Spherical aberration. A perfect lens focuses all incoming rays to a point on the [[Optical axis|optic axis]]. A real lens with spherical surfaces suffers from spherical aberration: it focuses rays more tightly if they enter it far from the optic axis than if they enter closer to the...

 is the same in every direction.

The receiver is located on a 900-ton platform which is suspended 150 m (500 ft) in the air above the dish by 18 cables running from three reinforced concrete
Reinforced concrete
Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...

 towers, one of which is 110 m (365 ft) high and the other two of which are 80 m (265 ft) high (the tops of the three towers are at the same elevation). The platform has a 93-meter-long rotating bow-shaped track called the azimuth arm on which receiving antennas, secondary and tertiary reflectors are mounted. This allows the telescope to observe any region of the sky within a forty-degree cone of visibility about the local zenith
Zenith
The zenith is an imaginary point directly "above" a particular location, on the imaginary celestial sphere. "Above" means in the vertical direction opposite to the apparent gravitational force at that location. The opposite direction, i.e...

 (between -1 and 38 degrees of declination
Declination
In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...

). Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...

's location near the equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....

 allows Arecibo to view all of the planets in the solar system, though the round trip light time to objects beyond Saturn
Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...

 is longer than the time the telescope can track it, preventing radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

 observations of more distant objects.

Design and architecture



The Arecibo telescope was built between the summer of 1960 and November, 1963, by William E. Gordon
William E. Gordon
William Edward Gordon was a physicist and astronomer. He is referred to as the "father of the Arecibo Observatory"....

 and Zachary Sears of Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

, who intended to use it to study Earth's ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...

. Originally, a fixed parabolic reflector was envisioned, pointing in a fixed direction with a 150 m (500 ft) tower to hold equipment at the focus. This design would have limited its use in other areas of research, such as planetary science
Planetary science
Planetary science is the scientific study of planets , moons, and planetary systems, in particular those of the Solar System and the processes that form them. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation,...

 and radio astronomy
Radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...

, which require the ability to point at different positions in the sky and to track those positions for an extended period as Earth rotates. Ward Low of the Advanced Research Projects Agency (ARPA) pointed out this flaw, and put Gordon in touch with the Air Force Cambridge Research Laboratory (AFCRL) in Boston, Massachusetts, where one group headed by Phil Blacksmith was working on spherical reflectors and another group was studying the propagation of radio wave
Radio Wave
Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...

s in and through the upper atmosphere. Cornell University proposed the project to ARPA in the summer of 1958 and a contract was signed between the AFCRL and the University in November 1959. Cornell University and Sears published a request for proposals asking for a design to support a feed moving along a spherical surface 435 feet (133 m) above the stationary reflector. The RFP suggested a tripod or a tower in the center to support the feed. At Cornell University on the day the project for the design and construction of the antenna was announced, Gordon had also envisioned a 435 ft (132.6 m) tower located in the center of the 1000 ft (304.8 m) reflector for the feed's support.

George Doundoulakis, who directed research at General Bronze Corporation in Garden City, New York, along with Sears, who directed Internal Design at Digital B & E Corporation, New York, received the RFP from Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

 for the antenna design, and studied the idea of suspending the feed with his brother, Helias Doundoulakis
Helias Doundoulakis
Helias Doundoulakis is a Greek American scientific innovator who patented the suspension system for the largest radio telescope in the world, and served in the United States Army as a spy for the Office of Strategic Services.-War years:...

, a civil engineer
Civil engineer
A civil engineer is a person who practices civil engineering; the application of planning, designing, constructing, maintaining, and operating infrastructures while protecting the public and environmental health, as well as improving existing infrastructures that have been neglected.Originally, a...

. George Doundoulakis identified the problem that a tower or tripod would have presented around the center, the most important area of the reflector, and devised a more efficient, cost-effective approach by suspending the feed. He presented his proposal to Cornell, by using a doughnut truss
Truss
In architecture and structural engineering, a truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. External forces and reactions to those forces are considered to act only at the nodes and result in...

 suspended by four cables from four towers above the reflector, and providing along its edge a rail track for the azimuthal positioning of the feed. A second truss
Truss
In architecture and structural engineering, a truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. External forces and reactions to those forces are considered to act only at the nodes and result in...

, in the form of an arc, or arch
Arch
An arch is a structure that spans a space and supports a load. Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture and their systematic use started with the Ancient Romans who were the first to apply the technique to a wide range of structures.-Technical aspects:The...

, was to be suspended below, which would rotate on the rails through 360 degrees. The arc also provided rails onto which the unit supporting the feed would move to provide for the elevational positioning of the feed. A counter-weight would move symmetrically opposite to the feed for stability, and the entire feed could be lowered and raised if a hurricane were present. Helias Doundoulakis
Helias Doundoulakis
Helias Doundoulakis is a Greek American scientific innovator who patented the suspension system for the largest radio telescope in the world, and served in the United States Army as a spy for the Office of Strategic Services.-War years:...

 ultimately designed the cable
Cable
A cable is two or more wires running side by side and bonded, twisted or braided together to form a single assembly. In mechanics cables, otherwise known as wire ropes, are used for lifting, hauling and towing or conveying force through tension. In electrical engineering cables are used to carry...

 suspension system which was adopted in the final construction. Although the present configuration is substantially the same as the original drawings by George and Helias (with the exception of the suspension of the feed positioning assembly by three towers rather than the four towers in the original proposal), the U.S. Patent office
United States Patent and Trademark Office
The United States Patent and Trademark Office is an agency in the United States Department of Commerce that issues patents to inventors and businesses for their inventions, and trademark registration for product and intellectual property identification.The USPTO is based in Alexandria, Virginia,...

 granted Helias a patent for the brothers' innovative idea. William J. Casey
William J. Casey
William Joseph Casey was the Director of Central Intelligence from 1981 to 1987. In this capacity he oversaw the entire United States Intelligence Community and personally directed the Central Intelligence Agency ....

, later to be the director of the Central Intelligence Agency
Central Intelligence Agency
The Central Intelligence Agency is a civilian intelligence agency of the United States government. It is an executive agency and reports directly to the Director of National Intelligence, responsible for providing national security intelligence assessment to senior United States policymakers...

 under President Ronald Reagan
Ronald Reagan
Ronald Wilson Reagan was the 40th President of the United States , the 33rd Governor of California and, prior to that, a radio, film and television actor....

, was also an assignee on the patent.

Construction began in the summer of 1960, with the official opening on November 1, 1963. As the primary dish is spherical, its focus is along a line rather than at a single point (as would be the case for a parabolic reflector
Parabolic reflector
A parabolic reflector is a reflective device used to collect or project energy such as light, sound, or radio waves. Its shape is that of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis...

); therefore, complicated line feeds had to be used to carry out observations. Each line feed covered a narrow frequency band (2-5% of the center frequency of the band) and a limited number of line feeds could be used at any one time, limiting the flexibility of the telescope.

The telescope has been upgraded several times. Initially, when the maximum expected operating frequency was about 500 MHz, the surface consisted of half-inch galvanized wire mesh laid directly on the support cables. In 1974, a high-precision surface consisting of thousands of individually adjustable aluminum panels replaced the old wire mesh, and the highest usable frequency was raised to about 5,000 MHz. A Gregorian
Gregorian telescope
The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke...

 reflector system was installed in 1997, incorporating secondary and tertiary reflectors to focus radio waves at a single point. This allowed the installation of a suite of receivers, covering the whole 1–10 GHz range, that could be easily moved onto the focal point
Focus (optics)
In geometrical optics, a focus, also called an image point, is the point where light rays originating from a point on the object converge. Although the focus is conceptually a point, physically the focus has a spatial extent, called the blur circle. This non-ideal focusing may be caused by...

, giving Arecibo a new flexibility. At the same time, a ground screen was installed around the perimeter to block the ground's thermal radiation from reaching the feed antennas, and a more powerful 2,400 MHz transmitter was installed.

Research and discoveries


Many significant scientific discoveries have been made using the Arecibo telescope. On 7 April 1964, shortly after it began operations, Gordon Pettengill
Gordon Pettengill
Gordon Pettengill is a noted American radio astronomer and planetary physicist.-Early life and education:Pettengill was born in Providence, Rhode Island. As a young man he was enthralled with radio and electronics, taking apart and building old radios...

's team used it to determine that the rotation
Rotation
A rotation is a circular movement of an object around a center of rotation. A three-dimensional object rotates always around an imaginary line called a rotation axis. If the axis is within the body, and passes through its center of mass the body is said to rotate upon itself, or spin. A rotation...

 rate of Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...

 was not 88 days, as previously thought, but only 59 days. In 1968, the discovery of the periodicity of the Crab Pulsar
Crab Pulsar
The Crab Pulsar is a relatively young neutron star. The star is the central star in the Crab Nebula, a remnant of the supernova SN 1054, which was widely observed on Earth in the year 1054...

 (33 milliseconds) by Lovelace and others provided the first solid evidence that neutron star
Neutron star
A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...

s exist. In 1974, Hulse
Russell Alan Hulse
Russell Alan Hulse is an American physicist and winner of the Nobel Prize in Physics, shared with his thesis advisor Joseph Hooton Taylor Jr., "for the discovery of a new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation"...

 and Taylor
Joseph Hooton Taylor, Jr.
Joseph Hooton Taylor, Jr. is an American astrophysicist and Nobel Prize in Physics laureate for his discovery with Russell Alan Hulse of a "new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation."...

 discovered the first binary pulsar PSR B1913+16, an accomplishment for which they later received the Nobel Prize
Nobel Prize
The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...

 in Physics. In 1982, the first millisecond pulsar
Millisecond pulsar
A millisecond pulsar is a pulsar with a rotational period in the range of about 1-10 milliseconds. Millisecond pulsars have been detected in the radio, X-ray, and gamma ray portions of the electromagnetic spectrum. The origin of millisecond pulsars is still unknown...

, PSR B1937+21
PSR B1937+21
PSR B1937+21 is a pulsar located in the constellation Vulpecula a few degrees in the sky away from the first discovered pulsar, PSR B1919+21. The name PSR B1937+21 is derived from the word "pulsar" and the declination and right ascension at which it is located, with the "B" indicating that the...

, was discovered by Donald C. Backer
Donald C. Backer
Donald C. Backer was an American astrophysicist who primarily worked in radio astronomy. Backer made important contributions to the understanding and study of pulsars, including the discovery of the first millisecond pulsar, black holes, and the epoch of reionization. -Biography:Backer was born in...

, Shrinivas Kulkarni
Shrinivas Kulkarni
Shrinivas R. Kulkarni FRS is a professor of astrophysics and planetary science at California Institute of Technology. He is on the Space Interferometry Mission science team and is the director of optical observatories at California Institute of Technology, including Palomar and Keck.Kulkarni is...

, Carl Heiles, Michael Davis, and Miller Goss. This object spins 642 times per second, and until the discovery of PSR J1748-2446ad in 2005, it was the fastest-spinning pulsar known.

In August 1989, the observatory directly imaged an asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

 for the first time in history: 4769 Castalia
4769 Castalia
The asteroid 4769 Castalia was the first asteroid to be modeled by radar imaging. It is an Apollo, Mars- and Venus-crosser asteroid. It was discovered on August 9, 1989, by Eleanor F. Helin on photographic plates taken at Palomar Observatory...

. The following year, Polish astronomer Aleksander Wolszczan
Aleksander Wolszczan
Aleksander Wolszczan is a Polish astronomer. He is the co-discoverer of the first extrasolar planets and pulsar planets.- Scientific career :...

 made the discovery of pulsar
Pulsar
A pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The radiation can only be observed when the beam of emission is pointing towards the Earth. This is called the lighthouse effect and gives rise to the pulsed nature that gives pulsars their name...

 PSR B1257+12, which later led him to discover its three orbiting planets and a possible comet. These were the first extra-solar planets
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...

 discovered. In 1994, John Harmon used the Arecibo radio telescope to map the distribution of ice in the poles of Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...

.

In January 2008, detection of prebiotic molecules methanimine and hydrogen cyanide were reported from Arecibo Observatory radio spectroscopy measurements of the distant starburst galaxy Arp 220
Arp 220
Arp 220 is the result of a collision between two galaxies which are now in the process of merging. Located 250 million light-years away in the constellation Serpens, it is the 220th object in Halton Arp's Atlas of Peculiar Galaxies.-Features:...

.

Other usage


The telescope also had military intelligence
Military intelligence
Military intelligence is a military discipline that exploits a number of information collection and analysis approaches to provide guidance and direction to commanders in support of their decisions....

 uses; among them, locating Soviet
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

 installations by detecting their signals bouncing
EME (communications)
Earth-Moon-Earth, also known as moon bounce, is a radio communications technique which relies on the propagation of radio waves from an Earth-based transmitter directed via reflection from the surface of the Moon back to an Earth-based receiver....

 off the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

.

Arecibo is also the source of data for the SETI@home and Astropulse
Astropulse
Astropulse is a distributed computing project that uses volunteers across the globe to lend their unused computing power to search for primordial black holes, pulsars, and ETI. Volunteer resources are harnessed through Berkeley Open Infrastructure for Network Computing platform...

 distributed computing
Distributed computing
Distributed computing is a field of computer science that studies distributed systems. A distributed system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal...

 projects put forward by the Space Sciences Laboratory at the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...

 and was used for the SETI Institute
SETI Institute
The SETI Institute is a not-for-profit organization whose mission is to “explore, understand and explain the origin, nature and prevalence of life in the universe”. SETI stands for the "search for extraterrestrial intelligence". One program is the use of both radio and optical telescopes to search...

's Project Phoenix
Project Phoenix (SETI)
Project Phoenix is a SETI project: a search for extraterrestrial intelligence by analyzing patterns in radio signals. It is run by the independently funded SETI Institute of Mountain View, California, USA....

 observations.

In 1974, the Arecibo message
Arecibo message
The Arecibo message was broadcast into space a single time via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope on 16 November 1974. It was aimed at the globular star cluster M13 some 25,000 light years away because M13 was a large and close...

, an attempt to communicate with potential extraterrestrial life
Extraterrestrial life
Extraterrestrial life is defined as life that does not originate from Earth...

, was transmitted from the radio telescope toward the globular cluster M13
Messier 13
Messier 13 or M13 is a globular cluster of about 300,000 stars in the constellation of Hercules....

, about 25,000 light-years away. The 1,679 bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

 pattern of 1s and 0s defined a 23 by 73 pixel bitmap image
Bitmap
In computer graphics, a bitmap or pixmap is a type of memory organization or image file format used to store digital images. The term bitmap comes from the computer programming terminology, meaning just a map of bits, a spatially mapped array of bits. Now, along with pixmap, it commonly refers to...

 that included numbers, stick figures, chemical formulas, and a crude image of the telescope itself. Terrestrial aeronomy experiments include the Coqui 2
NASA Coqui
The Coquí and Coquí 2 campaign involved a sequence of sounding rocket launches in order to study the dynamics of the E- and F-region ionosphere and increase our understanding of layering phenomena, such as sporadic E layers...

 experiment.

Funding issues



A report by the division of Astronomical Sciences of the National Science Foundation, made public on 2006-11-03, recommended substantially decreased astronomy funding for Arecibo Observatory, ramping down from US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....

10.5M in 2007 to US$4M in 2011. If other sources of money cannot be obtained, the observatory would close. The report also advised that 80% of the observation time be allocated to the surveys already in progress, reducing the time available for other scientific work. NASA gradually eliminated its share of the planetary radar funding at Arecibo from 2001–2006.

Academics and researchers responded by organizing to protect and advocate for the observatory. They established the Arecibo Science Advocacy Partnership (ASAP), meant to advance the scientific excellence of Arecibo Observatory research and to publicize its accomplishments in astronomy, aeronomy and planetary radar. ASAP's goals include mobilize the existing broad base of support for Arecibo science within the fields it serves directly, the broad scientific community, and the general public; provide a forum for the Arecibo research community and enhance communication within it; promote the potential of Arecibo for groundbreaking science, and suggest the paths that will maximize it into the foreseeable future; showcase the broad impact and far-reaching implications of the science currently carried out with this unique instrument.

Contributions by the government of Puerto Rico may be one way to help fill the funding gap, but are controversial and uncertain. At town hall meeting
Town hall meeting
A town hall meeting is an American English term given to an informal public meeting. Everybody in a town community is invited to attend, not always to voice their opinions, but to hear the responses from public figures and elected officials about shared subjects of interest. Attendees rarely voted...

s about the potential closure, Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...

 Senate President Kenneth McClintock
Kenneth McClintock
Kenneth D. McClintock-Hernández is the current Secretary of State of Puerto Rico. Mr. McClintock served as co-chair of Hillary Clinton presidential campaign's National Hispanic Leadership Council in 2008, co-chaired Clinton's successful Puerto Rico primary campaign that year and served as the...

 announced an initial local appropriation of $3 million during fiscal year 2008 to fund a major maintenance project to restore the three pillars from which the antenna platform is suspended to their original condition, pending inclusion in the next bond issue. The bond authorization, with the $3 million appropriation, was approved by the Senate of Puerto Rico
Senate of Puerto Rico
The Senate of Puerto Rico is the upper house of the Legislative Assembly of Puerto Rico, the territorial legislature of Puerto Rico. The Senate is composed of 27 senators, representing eight constituent senatorial districts across the commonwealth, with two senators elected per district; an...

 on November 14, 2007, the first day of a special session called by Aníbal Acevedo Vilá
Aníbal Acevedo Vilá
Aníbal Salvador Acevedo Vilá is a Puerto Rican politician and lawyer. He served as the eighth Governor of the Commonwealth of Puerto Rico, a Commonwealth of the United States, from 2005 to 2009. He is a Harvard University alumnus and a graduate of the University of Puerto Rico School of Law,...

. The Puerto Rico House of Representatives repeated this action on June 30, 2008. The Governor signed the measure into law in August 2008. These funds were made available in the second half of 2009.

José Serrano
José Serrano
José Enrique Serrano is the U.S. Representative for , serving since 1990. He is a member of the Democratic Party....

, a member of the U.S. House of Representatives Appropriations Committee
Appropriations Committee
In the United States government, the Appropriations Committee can refer to either:* the United States House Committee on Appropriations* the United States Senate Committee on Appropriations...

, asked the National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...

 to keep Arecibo in operation in a letter released on September 19, 2007. Language similar to that in the September 19 letter was included in the FY'08 omnibus spending bill. In October 2007, Puerto Rico's Resident Commissioner
Resident Commissioner
Resident Commissioner is the title of several, quite different types of Commissioner in overseas possession or protectorate of the British Crown or of the United States.-British English:...

 (now governor), Luis Fortuño
Luis Fortuño
Luis Guillermo Fortuño Burset is the governor of the Commonwealth of Puerto Rico, a territory of the United States of America. Fortuño is also the president of the New Progressive Party of Puerto Rico , a member of the Republican National Committee, and will be president of the Council of State...

, along with Dana Rohrabacher
Dana Rohrabacher
Dana Tyron Rohrabacher is the U.S. Representative for , and previously the 45th and 42nd, serving since 1989. He is a member of the Republican Party...

, filed legislation to assure the continued operation of the facility. A similar bill was filed in the United States Senate in April, 2008 by the junior Senator from New York, Hillary Clinton
Hillary Rodham Clinton
Hillary Diane Rodham Clinton is the 67th United States Secretary of State, serving in the administration of President Barack Obama. She was a United States Senator for New York from 2001 to 2009. As the wife of the 42nd President of the United States, Bill Clinton, she was the First Lady of the...

.

As the Arecibo facility is owned by the United States, direct donations by private or corporate donors cannot be made. However, as a non-profit, 403(c)(3) charitable institution, Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

 (and in the future, SRI International
SRI International
SRI International , founded as Stanford Research Institute, is one of the world's largest contract research institutes. Based in Menlo Park, California, the trustees of Stanford University established it in 1946 as a center of innovation to support economic development in the region. It was later...

) will accept contributions on behalf of Arecibo Observatory. It has been suggested by at least one member of the NAIC staff that Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...

 purchase advertising space on the dish as one means of securing additional non-government funds.

In September 2007, in an open letter to researchers, the NSF clarified the status of the budget issue for NAIC, stating that the present plan, if implemented, may hit the targeted budgetary revision. No mention of private funding was made. However, it need be noted that the NSF is undertaking studies to mothball, or deconstruct the facility and return it to its natural setting in the event that the budget target is not achieved. In November 2007, The Planetary Society urged Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

 to prevent the Arecibo Observatory from closing due to insufficient funds, since the radar contributes heavily to the accuracy of asteroid impact prediction, and they believe continued operation will reduce the cost of mitigation (that is, deflection of a near-earth asteroid on collision to Earth), should that be necessary.

In July 2008, the British newspaper The Daily Telegraph
The Daily Telegraph
The Daily Telegraph is a daily morning broadsheet newspaper distributed throughout the United Kingdom and internationally. The newspaper was founded by Arthur B...

reported that the funding crisis, due to federal budget cuts, was still very much alive. The SETI@home
SETI@home
SETI@home is an Internet-based public volunteer computing project employing the BOINC software platform, hosted by the Space Sciences Laboratory, at the University of California, Berkeley, in the United States. SETI is an acronym for the Search for Extra-Terrestrial Intelligence...

 program is using the telescope as a primary source for the research. The program is urging people to send a letter to their political representatives, in support of full federal funding of the observatory.

NAIC received US$3.1 million from the American Recovery and Reinvestment Act of 2009
American Recovery and Reinvestment Act of 2009
The American Recovery and Reinvestment Act of 2009, abbreviated ARRA and commonly referred to as the Stimulus or The Recovery Act, is an economic stimulus package enacted by the 111th United States Congress in February 2009 and signed into law on February 17, 2009, by President Barack Obama.To...

, which was used for infrastructure improvements and for a second, much smaller, antenna to be used for VLBI and student training. This allotment was an increase of around 30% over the FY2009 budget. However, the FY2010 funding request by NSF was cut by US$1.2 million (-12.5% over the non-ARRA supported FY2009 budget) in light of their continued plans to reduce funding.
The 2011 NSF budget request is reduced by a further US$1.6 million, -15% with respect to 2010, with a further US$1 million reduction projected by FY2014. In addition, "NSF will decertify NAIC as a Federally Funded Research and Development Center (FFRDC) upon award of the next cooperative agreement for its management and operation."

The FY 2010 NASA budget included $2M for Arecibo. NASA is implementing this funding through its Near Earth Object Observations program.

In 2010, the National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...

 issued a call for proposals for the management of NAIC beginning in FY2012. On May 12, 2011, The National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...

 informed Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

 that it would no longer be the operator of the NAIC, and thus of the Arecibo Observatory, as of October 1, 2011. The new operator is SRI International
SRI International
SRI International , founded as Stanford Research Institute, is one of the world's largest contract research institutes. Based in Menlo Park, California, the trustees of Stanford University established it in 1946 as a center of innovation to support economic development in the region. It was later...

, along with two other managing partners, Universities Space Research Association
Universities Space Research Association
The Universities Space Research Association was incorporated on March 12, 1969 in the District of Columbia as a private, nonprofit corporation under the auspices of the National Academy of Sciences . Institutional membership in the Association has grown from 49 colleges and universities when it was...

 and Universidad Metropolitana, with a number of other collaborators.

In popular culture

  • The Arecibo Observatory was featured on Cosmos: A Personal Voyage
    Cosmos: A Personal Voyage
    Cosmos: A Personal Voyage is a thirteen-part television series written by Carl Sagan, Ann Druyan, and Steven Soter, with Sagan as presenter. It was executive-produced by Adrian Malone, produced by David Kennard, Geoffrey Haines-Stiles and Gregory Andorfer, and directed by the producers, David...

     in Part 12 "Encyclopaedia Galactica."
  • The Arecibo Observatory is featured at the end of James Burke's TV series Connections
    Connections (TV series)
    Connections is a ten-episode documentary television series created, written and presented by science historian James Burke. The series was produced and directed by Mick Jackson of the BBC Science & Features Department and first aired in 1978 and 1979...

    in Part 3 "Distant Voices."
  • Arecibo Observatory was used as a filming location in the climax of the James Bond
    James Bond
    James Bond, code name 007, is a fictional character created in 1953 by writer Ian Fleming, who featured him in twelve novels and two short story collections. There have been a six other authors who wrote authorised Bond novels or novelizations after Fleming's death in 1964: Kingsley Amis,...

     movie GoldenEye
    GoldenEye
    GoldenEye is the seventeenth spy film in the James Bond series, and the first to star Pierce Brosnan as the fictional MI6 agent James Bond. The film was directed by Martin Campbell and is the first film in the series not to take story elements from the works of novelist Ian Fleming...

    and as a level in the accompanying Nintendo 64 videogame GoldenEye 007.
  • The film Contact
    Contact (film)
    Contact is a 1997 American science fiction drama film adapted from the Carl Sagan novel of the same name and directed by Robert Zemeckis. Both Sagan and wife Ann Druyan wrote the story outline for the film adaptation of Contact....

    features Arecibo, where the main character uses the facility as part of a SETI
    SETI
    The search for extraterrestrial intelligence is the collective name for a number of activities people undertake to search for intelligent extraterrestrial life. Some of the most well known projects are run by the SETI Institute. SETI projects use scientific methods to search for intelligent life...

     project.
  • Fox Mulder
    Fox Mulder
    FBI Special Agent Fox William Mulder is a fictional character and protagonist in the American Fox television shows The X-Files and The Lone Gunmen, two science fiction shows about a government conspiracy to hide or deny the truth of Alien existence. Mulder's peers consider his theories on...

     was sent to the Arecibo Observatory in The X-Files
    The X-Files
    The X-Files is an American science fiction television series and a part of The X-Files franchise, created by screenwriter Chris Carter. The program originally aired from to . The show was a hit for the Fox network, and its characters and slogans became popular culture touchstones in the 1990s...

    episode "Little Green Men".
  • Songwriter and author Jimmy Buffett
    Jimmy Buffett
    James William "Jimmy" Buffett is a singer-songwriter, author, entrepreneur, and film producer. He is best known for his music, which often portrays an "island escapism" lifestyle. Together with his Coral Reefer Band, Buffett's musical hits include "Margaritaville" , and "Come Monday"...

     mentions the "giant telescope" in his book Where Is Joe Merchant?
    Where Is Joe Merchant?
    Where is Joe Merchant? is a novel by singer Jimmy Buffett, published in 1992. The book, a New York Times Best Seller, revolves around Frank Bama and his ex-girlfriend, hemorrhoid-ointment heiress Trevor Kane...

    , and in the lyrics to the song "Desdemona's Building A Rocket Ship".
  • The musicians Boxcutter
    Boxcutter (musician)
    Boxcutter is the pseudonym for Barry Lynn , an electronic musician from Northern Ireland whose work, due to its bass-led and rhythmically 2-step nature, is often categorised as dubstep, although in style and idiosyncrasies has more in common with IDM artists such as Squarepusher and µ-Ziq.-...

    , Lustmord
    Lustmord
    Brian Williams is a British electronic musician often credited for creating the dark ambient genre with albums recorded under the name Lustmord.- History :Williams started recording as Lustmord in 1980 before joining SPK in 1982...

    , and Little Boots
    Little Boots
    Victoria Christina Hesketh, also known by her stage name/pseudonym Little Boots, is an English electropop singer-songwriter. Her stage name comes from a nickname given to her by a friend, a reference to her unusually small feet...

     have all released albums named Arecibo.
  • The observatory is featured in the film Species
    Species (film)
    Species is a 1995 science fiction horror film directed by Roger Donaldson, and starring Ben Kingsley, Michael Madsen, Alfred Molina, Forest Whitaker, Marg Helgenberger, and Natasha Henstridge...

    , the James Gunn
    James Gunn (author)
    - Further reading :James E. Gunn The Listeners, BenBella Books, ISBN 1-932100-12-1 -External links:*...

     novel The Listeners
    The Listeners (novel)
    The Listeners is a science fiction novel by American author James Gunn. It centers on the search for interstellar communication and the effect that receipt of a message has...

    (1972), the Robert J. Sawyer
    Robert J. Sawyer
    Robert James Sawyer is a Canadian science fiction writer. He has had 20 novels published, and his short fiction has appeared in Analog Science Fiction and Fact, Amazing Stories, On Spec, Nature, and many anthologies. Sawyer has won over forty awards for his fiction, including the Nebula Award ,...

     novel Rollback, and the Mary Doria Russell
    Mary Doria Russell
    Mary Doria Russell is an American novelist. -Biography:Russell was born in the suburbs of Chicago. Her parents were both in the military: her father was a Marine Corps drill instructor, and her mother was a Navy nurse. She graduated from Glenbard East High School and later she earned a Ph.D in...

     novel The Sparrow.
  • Arecibo Observatory also featured in the action movie The Losers
    The Losers (film)
    The Losers is a 2010 American action based on the adaptation of the Vertigo comic book series of the same name by Andy Diggle. Directed by Sylvain White, the film features an ensemble cast that includes Jeffrey Dean Morgan, Zoe Saldana and Chris Evans....

    (2010).
  • In the video game Just Cause 2
    Just Cause 2
    Just Cause 2 is an open world action-adventure video game developed by Avalanche Studios, published by Eidos Interactive, and distributed by Square Enix. It is the sequel to the 2006 video game Just Cause....

     there is a large radio observatory called PAN MILSAT that is very similar in appearance to Arecibo Observatory.
  • The Third Twin (project) has a song called "Arecibo's Song".
  • Internet radio station Arecibo Radio is named after the observatory.

See also


  • UPRM Planetarium
  • Air Force Research Laboratory
    Air Force Research Laboratory
    The Air Force Research Laboratory is a scientific research organization operated by the United States Air Force Materiel Command dedicated to leading the discovery, development, and integration of affordable aerospace warfighting technologies; planning and executing the Air Force science and...

  • List of radio telescopes
  • Sixto Gonzalez
    Sixto Gonzalez
    Dr. Sixto González was the first Puerto Rican to be named Director of the Arecibo Observatory, the world's largest single dish radio telescope.-Early years:...

    , former director of the Arecibo Observatory
  • Tor Hagfors
    Tor Hagfors
    Tor Hagfors was a Norwegian scientist, radio astronomer, radar expert and a pioneer in the studies of the interactions between electromagnetic waves and a plasma. He was one of several theorists who developed the theory underlying incoherent scattering in the early 1960s.Tor Hagfors was born in...

    , former director of NAIC
  • William E. Gordon
    William E. Gordon
    William Edward Gordon was a physicist and astronomer. He is referred to as the "father of the Arecibo Observatory"....

    , founder and first director of the observatory
  • Helias Doundoulakis
    Helias Doundoulakis
    Helias Doundoulakis is a Greek American scientific innovator who patented the suspension system for the largest radio telescope in the world, and served in the United States Army as a spy for the Office of Strategic Services.-War years:...

    U.S. Patent Office 3,273,156 (1966-09-13) Helias Doundoulakis, Radio Telescope having a scanning feed supported by a cable suspension over a stationary reflector.

Further reading

telescope
|author=Blaine Friedlander
|publisher=EurekAlert
|date=June 10, 2008}}

External links