The Info List - Arecibo Observatory

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The Arecibo Observatory
is a radio telescope in the municipality of Arecibo, Puerto Rico. This observatory is operated by SRI International, USRA and UMET, under cooperative agreement with the National Science Foundation
National Science Foundation
(NSF).[3][4] The observatory is the sole facility of the National Astronomy
and Ionosphere
Center (NAIC), which is the formal name of the observatory.[5] From its construction in the 1960s until 2011, the observatory was managed by Cornell University. For more than 50 years, the observatory's 1,000-foot (305-meter) radio telescope was the world's largest single-aperture telescope, from its completion in 1963 until July 2016 when the Five hundred meter Aperture Spherical
Telescope (FAST) in China was completed. It is used in three major areas of research: radio astronomy, atmospheric science, and 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, gaming 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 American National Register of Historic Places
National Register of Historic Places
starting in 2008.[2][6] It was the featured listing in the National Park Service's weekly list of October 3, 2008.[7] The center was named an IEEE
Milestone in 2001.[8] It has a visitor center that is open part-time.[9] 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.[10][11][12][13]


1 General information 2 Design and architecture 3 Research and discoveries 4 SETI, METI

4.1 The Arecibo Message 4.2 The RuBisCo Stars 4.3 SETI
and METI projects

5 Other uses 6 Funding concerns 7 Ángel Ramos Foundation Visitor Center 8 List of directors 9 In popular culture 10 See also 11 References 12 Further reading 13 External links

General information[edit] The main collecting dish is 305 m (1,000 ft) in diameter, constructed inside the depression left by a karst sinkhole.[14] The dish surface is made of 38,778 perforated aluminum panels, each about 3 by 6 feet (1 by 2 m), supported by a mesh of steel cables. The ground beneath is accessible and supports shade-tolerant vegetation.[15] The observatory has four radar transmitters, with effective isotropic radiated powers of 20 TW (continuous) at 2380 MHz, 2.5 TW (pulse peak) at 430 MHz, 300 MW at 47 MHz, and 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 (870 ft) radius.[16] 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 (492 ft) above the dish by 18 cables running from three reinforced concrete towers, one 111 m (365 ft) high and the other two 81 m (265 ft) high, placing their tops at the same elevation. The platform has a rotating, bow-shaped track 93 m (305 ft) 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 (between −1 and 38 degrees of declination). 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 Arecibo Radio Telescope as viewed from the observation deck, October 2013

Design and architecture[edit]

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A detailed view of the beam-steering mechanism and some antennas. The triangular platform at the top is fixed, and the azimuth arm rotates beneath it. To the left is the Gregorian sub-reflector, and to the right is the 96-foot-long (29 m) line feed tuned to 430 MHz. Just visible at the upper right is part of the rectangular waveguide that brings the 2.5 MW 430 MHz radar transmitter's signal up to the focal region.

The origins of the observatory trace to late 1950s efforts to develop anti-ballistic missile (ABM) defences as part of the newly formed ARPA's ABM umbrella-effort, Project Defender. Even at this early stage it was clear that the use of radar decoys would be a serious problem at the long ranges needed to successfully attack a warhead, ranges on the order of 1,000 miles (1,600 km).[17][18] 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, and 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.[17][18] Although the concept appeared to offer a solution to the tracking problem, there was almost 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 also producing a general-purpose scientific radio observatory.[17][18] The observatory was built between mid-1960 and November 1963 and designed by William E. Gordon
William E. Gordon
of Cornell University, who intended to use it to study Earth's ionosphere. He was attracted to the sinkholes in the karst regions of Puerto Rico
Puerto Rico
that offered perfect cavities for a very large dish.[19][20][21] Originally, a fixed parabolic reflector was envisioned, pointing in a fixed direction with a 150 m (492 ft) 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 (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 waves in and through the upper atmosphere. Cornell University proposed the project to ARPA in mid-1958 and a contract was signed between the AFCRL and the University in November 1959. Cornell University and Zachary Sears published a request for proposals (RFP) 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. On the day the project for the design and construction of the antenna was announced at Cornell University, Gordon had also envisioned a 435 ft (133 m) tower centered in the 1,000 ft (305 m) reflector to support the feed. George Doundoulakis, who directed research at General Bronze Corporation in Garden City, New York, along with Zachary Sears, who directed Internal Design at Digital B & E Corporation, New York, received the RFP from Cornell University
Cornell University
for the antenna design and studied the idea of suspending the feed with his brother, Helias Doundoulakis, a civil engineer. 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 better design by suspending the feed. He presented his proposal to Cornell University for a doughnut truss suspended by four cables from four towers above the reflector, having along its edge a rail track for the azimuth truss positioning. This second truss, in the form of an arc, or arch, was to be suspended below, which would rotate on the rails through 360 degrees. The arc also had rails on which the unit supporting the feed would move for the feed's elevational positioning. A counterweight would move symmetrically opposite to the feed for stability and, if a hurricane struck, the whole feed could be raised and lowered. Helias Doundoulakis
Helias Doundoulakis
designed the cable suspension system which was finally adopted. Although the present configuration is substantially the same as the original drawings by George and Helias Doundoulakis, (although with three towers, instead of the original four as drawn in the original patent), the U.S. Patent office granted Helias Doundoulakis
Helias Doundoulakis
a patent,[22] for the brothers' innovative idea. Two other assignees on the patent were friends William J. Casey, who later became director of the Central Intelligence Agency
Central Intelligence Agency
under President Ronald Reagan, and Constantine Michalos, an attorney. The idea of a spherical reflecting mirror with a steerable secondary has since been used in optical telescopes, in particular the Hobby–Eberly Telescope
Hobby–Eberly Telescope
and the Southern African Large Telescope. Construction began in mid-1960, with the official opening on November 1, 1963.[23] As the primary dish is spherical, its focus is along a line rather than at one point, as would be the case for a parabolic reflector. As a result, complex line feeds were implemented to carry out observations. Each line feed covered a narrow frequency band: 2–5% of the center frequency of the band. A limited number of line feeds could be used at any one time, limiting the telescope's flexibility. Since then, 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 40,000 individually adjustable aluminum panels replaced the old wire mesh, and the highest usable frequency rose to about 5000 MHz. A Gregorian reflector system was installed in 1997, incorporating secondary and tertiary reflectors to focus radio waves at one point. This allowed installing a suite of receivers, covering the full 1–10 GHz range, that could be easily moved to the focal point, giving Arecibo more flexibility. A metal mesh screen was also installed around the perimeter to block the ground's thermal radiation from reaching the feed antennas. Finally, a more powerful 2400 MHz transmitter was added. Research and discoveries[edit]

The Arecibo message
Arecibo message
with added color to highlight the separate parts. The actual binary transmission carried no color information.

Many scientific discoveries have been made with the observatory. On April 7, 1964, soon after it began operating, Gordon Pettengill's team used it to determine that the rotation period of Mercury was not 88 days, as formerly thought, but only 59 days.[24] In 1968, the discovery of the periodicity of the Crab Pulsar
Crab Pulsar
(33 milliseconds) by Lovelace and others provided the first solid evidence that neutron stars exist.[25] In 1974, Hulse and Taylor discovered the first binary pulsar PSR B1913+16,[26] an accomplishment for which they later received the Nobel Prize in Physics. In 1982, the first millisecond pulsar, PSR B1937+21, was discovered by Donald C. Backer, Shrinivas Kulkarni, Carl Heiles, Michael Davis, and Miller Goss.[27] This object spins 642 times per second and, until the discovery of PSR J1748-2446ad in 2005, was identified as the fastest-spinning pulsar. In August 1989, the observatory directly imaged an asteroid for the first time in history: 4769 Castalia.[28] The following year, Polish astronomer Aleksander Wolszczan
Aleksander Wolszczan
made the discovery of pulsar PSR B1257+12, which later led him to discover its three orbiting planets.[29] These were the first extrasolar planets discovered. In 1994, John Harmon used the Arecibo Radio Telescope to map the distribution of ice in the polar regions of Mercury.[30] In January 2008, detection of prebiotic molecules methanimine and hydrogen cyanide were reported from the observatory's radio spectroscopy measurements of the distant starburst galaxy Arp 220.[31] From January 2010
to February 2011, American astronomers Matthew Route and Aleksander Wolszczan
Aleksander Wolszczan
detected bursts of radio emission from the T6.5 brown dwarf 2MASS J10475385+2124234. This was the first time that radio emission had been detected from a T dwarf, which has methane absorption lines in its atmosphere. It is also the coolest brown dwarf (at a temperature of ~900K) from which radio emission has been observed. The highly polarized and highly energetic radio bursts indicated that the object has a >1.7 kG-strength magnetic field and magnetic activity similar to both the planet Jupiter
and the Sun.[32] SETI, METI[edit] The Arecibo Message[edit] Main article: Arecibo Message In 1974, the Arecibo Message, an attempt to communicate with potential extraterrestrial life, was transmitted from the radio telescope toward the globular cluster Messier 13, about 25,000 light-years away.[33] The 1,679 bit pattern of 1s and 0s defined a 23 by 73 pixel bitmap image that included numbers, stick figures, chemical formulas and a crude image of the telescope.[34] The RuBisCo Stars[edit] Main article: RuBisCo Stars On November 7, 2009, as part of the 35th anniversary of the Drake/Sagan transmission to M13, the RuBisCO
gene sequence was transmitted to three nearby stars: GJ 83.1, Teagarden's star SO 025300.5+165258 and Kappa Ceti (G5B). The project was by artist Joe Davis with support from Paul Gilster, the Arecibo Observatory, Cornell University and others. SETI
and METI projects[edit] Main articles: SETI
and Active SETI Search for Extra-Terrestrial Intelligence
Search for Extra-Terrestrial Intelligence
(SETI)[35] is the search for extraterrestrial life or advanced technologies. SETI
aims to answer the question "Are we alone in the Universe?" by scanning the skies for transmissions from intelligent civilizations elsewhere in our galaxy. In comparison, METI (Messaging to Extra-Terrestrial Intelligence) refers to the active search by transmitting messages. Arecibo is the source of data for the SETI@home
and Astropulse distributed computing projects put forward by the Space Sciences Laboratory at the University of California, Berkeley
University of California, Berkeley
and was used for the SETI
Institute's Project Phoenix observations.[36] The Einstein@Home distributed computing project has found more than 20 pulsars in Arecibo data.[37] Other uses[edit] Terrestrial aeronomy experiments at Arecibo have included the Coqui 2 experiment, supported by NASA. The telescope also has military intelligence uses, some of which include locating Soviet radar installations by detecting their signals bouncing off the Moon.[38] Limited amateur radio operations have occurred, using moon bounce or Earth–Moon–Earth communication, in which radio signals aimed at the Moon
are reflected back to Earth. The first of these operations was on June 13–14, 1964, using the call KP4BPZ. A dozen or so two-way contacts were made on 144 and 432 MHz. On July 3 and July 24, 1965, KP4BPZ was again activated on 432 MHz, making approximately 30 contacts on 432 MHz during the limited time slots available. For these tests, a very wide-band instrumentation recorder captured a large segment of the receiving bandwidth, enabling later verification of other amateur station callsigns. These were not two-way contacts. From April 16–18, 2010, again, the Arecibo Amateur Radio Club KP4AO conducted moon-bounce activity using the antenna.[39] On November 10, 2013, the KP4AO Arecibo Amateur Radio Club conducted a Fifty-Year Commemoration Activation, lasting 7 hours on 14.250 MHz SSB, without using the main dish antenna. Funding concerns[edit] Since the early 1970s, the Arecibo Observatory
has been supported by the NSF ( National Science Foundation
National Science Foundation
divisions of Astronomical Sciences and of Atmospheric Sciences) with incremental support by NASA, for operating the planetary radar.[40] Between 2001 and 2006, NASA
decreased, then eliminated, its support of the planetary radar,[41] but restored and increased the funding in FY-2010. A report by the NSF division of Astronomical Sciences, made public on November 3, 2006, recommended substantially decreased astronomy funding for the Arecibo Observatory, from $10.5 million in 2007 to $4.0 million in 2011.[42][43] If other sources of money could not be obtained, the observatory would be forced to close. The report also advised that 80 percent of observing time be allocated to the surveys already in progress, reducing available time for smaller programs. Academics and researchers responded by organizing to protect and advocate for the observatory. They established the Arecibo Science Advocacy Partnership (ASAP), to advance the scientific excellence of Arecibo Observatory
research and to publicize its accomplishments in astronomy, aeronomy and planetary radar.[44] ASAP's goals included mobilizing the existing broad base of support for Arecibo science within the fields it serves directly, the broad scientific community; provide a forum for the Arecibo research community and enhance communication within it; promote the potential of Arecibo for groundbreaking science; suggest paths that will maximize it into the foreseeable future, and showcase the broad impact and far-reaching implications of the science currently carried out with this unique instrument.[44] Contributions by the government of Puerto Rico
Puerto Rico
may be one way to help fill the funding gap, but remain controversial and uncertain. At town hall meetings about the potential closure, Puerto Rican Senate President Kenneth McClintock
Kenneth McClintock
announced an initial local appropriation of $3.0 million during fiscal year 2008 to fund a major maintenance project to restore the three pillars that support the antenna platform to their original condition, pending inclusion in the next bond issue.[45] The bond authorization, with a $3.0 million appropriation, was approved by the Senate of Puerto Rico
Puerto Rico
on November 14, 2007, on the first day of a special session called by Aníbal Acevedo Vilá.[46] The Puerto Rico
Puerto Rico
House of Representatives repeated this action on June 30, 2008. Puerto Rico's governor signed the measure into law in August 2008.[47] These funds were made available during the second half of 2009. In a letter published on September 19, 2007, José Enrique Serrano, a member of the U.S. House of Representatives
U.S. House of Representatives
Appropriations Committee, asked the National Science Foundation
National Science Foundation
to keep Arecibo operating.[48] Language similar to that of the letter of September 19 was included in the FY-2008 omnibus spending bill. In October 2007, Puerto Rico's then-Resident Commissioner, Luis Fortuño, along with Dana Rohrabacher, filed legislation to assure the continued operation of the famed observatory.[49] A similar bill was filed in the U.S. Senate in April 2008 by the Junior Senator from New York, Hillary Clinton.[50] Since the Arecibo observatory is owned by the Government of the United States, donations by private or corporate donors cannot be made. However, as non-profit (501(c)(3)) "public charities" under US law, the operators, SRI International
SRI International
and Universidad Metropolitana, can accept contributions on behalf of the Arecibo Observatory.[51] In September 2007, in an open letter to researchers, the NSF clarified the status of the budget for NAIC, stating the present plan could hit the targeted budgetary revision.[52] No mention of private funding was made. However, in the event that its budget target is not reached, it must be noted that the NSF is undertaking studies to mothball or demolish the observatory to return it to its natural setting. In November 2007, The Planetary Society
The Planetary Society
urged the U.S. Congress
U.S. Congress
to prevent the Arecibo Observatory
from closing because of insufficient funding, since its radar contributes greatly to the accuracy of predictions of asteroid impacts on the Earth.[53] The Planetary Society believes that continued operation of the observatory will reduce the cost of mitigation (that is, deflection of a near-Earth asteroid on collision to Earth), should that be necessary. Also in November of that year The New York Times
The New York Times
described the consequences of the budget cuts at the site.[54] In July 2008, the British newspaper The Daily Telegraph
The Daily Telegraph
reported that the funding crisis, due to federal budget cuts, was still very much alive.[55] The SETI@home
program is using the telescope as a primary source for ET research. The program urges people to send a letter to their political representatives in support of full federal funding of the observatory.[56] The NAIC received $3.1 million from the American Recovery and Reinvestment Act of 2009. This was used for basic maintenance and for a second, much smaller, antenna to be used for very long baseline interferometry, new Klystron
amplifiers for the planetary radar system and student training.[57] This allotment was an increase of about 30 percent over the FY-2009 budget. However, the FY- 2010
funding request by NSF was cut by $1.2 million (−12.5%) over the FY-2009 budget, in light of their continued plans to reduce funding.[58] The 2011 NSF budget was reduced by a further $1.6 million, −15% compared to 2010, with a further $1.0 million reduction projected by FY-2014.[59] Starting in FY-2010, NASA
restored its historical support by contributing $2.0 million per year for planetary science, particularly the study of near-Earth objects, at Arecibo. NASA implemented this funding through its Near Earth Object Observations program.[60] NASA
increased its support to $3.5 million per year in 2012. Furthermore, in 2010
the NSF issued a call for new proposals for the management of NAIC starting in FY-2012.[5] On May 12, 2011, the agency informed Cornell University
Cornell University
that, as of October 1, 2011, it would no longer be the operator of the NAIC and the Arecibo Observatory. At that time, Cornell transferred its operations to SRI International, along with two other managing partners, Universities Space Research Association and Universidad Metropolitana de Puerto Rico, with a number of other collaborators.[4][61] Upon the award of the new cooperative agreement for NAIC management and operation, NSF also decertified NAIC as a Federally Funded Research and Development Center (FFRDC),[59] with the stated goal of providing the NAIC with greater freedom to establish broader scientific partnerships and pursue funding opportunities for activities beyond the scope of those supported by NSF.[62] In October 2015, the NSF released a "Dear Colleague Letter" reiterating its desire for a "substantially reduced funding commitment from NSF".[63] On September 30, 2016, the NSF released a followup to the October 2015 "Dear Colleague Letter" announcing a solicitation for future operation of the Observatory
stating "The subject Solicitation will request the submission of formal proposals involving the continued operation of Arecibo Observatory
under conditions of a substantially reduced funding commitment from NSF."[64] The damage sustained from Hurricane Maria
Hurricane Maria
in September 2017 further clouded the observatory's future. Although the damage was minimal,[12][13] restoring all the previous capabilities required more than the observatory's already-threatened operating budget, and users feared the decision would be made to decommission it instead.[65] However, it was announced in February 2018 that a consortium led by the University of Central Florida
University of Central Florida
will allow the NSF to reduce its contribution towards Arecibo's operating costs from $8 million to $2 million from the fiscal year 2022–2023, with the shortfall made up by the consortium partners, thus securing the observatory's future.[66] Ángel Ramos Foundation Visitor Center[edit]

Logo of the observatory at the entrance gate

Opened in 1997, the Ángel Ramos Foundation Visitor Center features interactive exhibits and displays about the operations of the radio telescope, astronomy and atmospheric sciences.[67] The center is named after the financial foundation that honors Ángel Ramos, owner of the El Mundo newspaper and founder of Telemundo. The Foundation provided half of the funds to build the Visitor Center, with the remainder received from private donations and Cornell University. The center, in collaboration with the Caribbean Astronomical Society,[68] host a series of Astronomical Nights throughout the year, which feature diverse discussions regarding exoplanets, and astronomical phenomena and discoveries (such as Comet ISON). The main purpose of the center is to increase public interest in astronomy, the observatory's research successes, and space endeavors. List of directors[edit]

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1960–1965, William E. Gordon 1965–1966, John W. Findlay 1966–1968, Frank Drake 1968–1971, Gordon Pettengill 1971–1973, Tor Hagfors 1973–1982, Harold D. Craft Jr. 1982–1987, Donald B. Campbell 1987–1988, Riccardo Giovanelli 1988–1992, Michael M. Davis 1992–2003, Daniel R. Altschuler (es) 2003–2006, Sixto A. González 2006–2007, Timothy L. Hankins 2007–2008, Robert B. Kerr 2008–2011, Michael C. Nolan 2011–2015, Robert B. Kerr 2016–present Francisco Córdova

In popular culture[edit] Due to its unique shape and concept the observatory is featured in many movies, video games and novels.

The observatory was featured on Cosmos: A Personal Voyage in part 12, "Encyclopedia Galactica". The observatory was used as a filming location in the climax of the James Bond
James Bond
movie GoldenEye
(1995), and as a level in the accompanying Nintendo 64
Nintendo 64
video game GoldenEye
007. The film Contact (1997), based on the Carl Sagan
Carl Sagan
1985 novel of the same name, features the main character using the observatory as part of a SETI
project. The 1998 film The Survivor features the observatory as an interplanetary gateway that the protagonist Tharkin is sent to when he is condemned to life imprisonment on Earth Fox Mulder
Fox Mulder
went to the observatory in The X-Files
The X-Files
episode, "Little Green Men". The observatory is featured in the film Species (1995), the James Gunn novel The Listeners (1972), the Robert J. Sawyer
Robert J. Sawyer
novel Rollback, the Mary Doria Russell
Mary Doria Russell
novel The Sparrow (1996) and the film The Losers (2010). A radio telescope based on the observatory is featured in the videogame Just Cause 2. Although never specifically named, the first lines of the Arthur C. Clarke novel 2010: Odyssey Two strongly imply that the opening scene takes place at the observatory. However, for the 1984 film adaptation, this scene was filmed at the Very Large Array
Very Large Array
in New Mexico. The Battlefield 4
Battlefield 4
multiplayer map, Rogue Transmission, is inspired by the observatory. The movie of The Losers has one scene filmed in the observatory. Jimmy Buffett's novel Where Is Joe Merchant? includes a character named Desdemona who once worked at the observatory, where she began receiving telepathic messages from outer space. Buffett also wrote a song about her, called "Desdemona's Building A Rocket Ship". In the game Supertuxkart
there is a level called Alien Signal featuring a giant telescope in a natural sinkhole inspired by the observatory.

See also[edit]

Puerto Rico
Puerto Rico

Air Force Research Laboratory Atacama Large Millimeter Array
Atacama Large Millimeter Array
(Chile) RATAN-600
(Russia) Five hundred meter Aperture Spherical Telescope
Five hundred meter Aperture Spherical Telescope
(China) UPRM Planetarium List of radio telescopes Helias Doundoulakis[69] Sixto González, former director of the observatory (2003–2006) Tor Hagfors, former director of the observatory (1971–1973) and also of NAIC (October 1982 to September 1992). William E. Gordon, founder and first director of the observatory (AIO 1960–1965)


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(2012). "The Arecibo Detection of the Coolest Radio-flaring Brown Dwarf". The Astrophysical Journal Letters. 747 (2): L22–L25. arXiv:1202.1287 . Bibcode:2012ApJ...747L..22R. doi:10.1088/2041-8205/747/2/L22.  ^ Larry Klaes (November 30, 2005). "Making Contact". Ithaca Times. Archived from the original on December 5, 2008. Retrieved 2008-09-02.  ^ Geaorge Cassiday. "The Arecibo Message". The University of Utah: Department of Physics. Archived from the original on January 17, 2010. Retrieved 2007-07-27.  ^ J. Tarter (2001). The Search For Extraterrestrial Intelligence (SETI). Annual Review of Astronomy
and Astrophysics. Vol. 39, pp. 511–548 doi:10.1146/annurev.astro.39.1.511 ^ Peter Backus (April 14, 2003). "Project Phoenix: SETI
Prepares to Observe at Arecibo". Space.com. Archived from the original on December 4, 2008. Retrieved 2008-09-02.  ^ " Einstein@Home new discoveries and detections of known pulsars in the BRP4 search". Einstein@Home. August 27, 2012. Retrieved August 28, 2012.  ^ Steve Blank "Secret history of Silicon Valley" talk ^ "ARRL; Moonbounce for everyone". Retrieved January 10, 2013.  ^ Butrica, Andrew J. (1996). " NASA
SP-4218: To See the Unseen – A History of Planetary Radar
Astronomy". NASA. Archived from the original on November 1, 2007. Retrieved August 6, 2014.  ^ Robert Roy Britt (20 December 2001). " NASA
Trims Arecibo Budget, Says Other Organizations Should Support Asteroid
Watch". Space.com. Imaginova. Archived from the original on December 5, 2008. Retrieved 2008-07-08.  ^ Blandford, Roger (22 October 2006). "From the Ground Up: Balancing the NSF Astronomy
Program" (PDF). National Science Foundation. Archived (PDF) from the original on June 26, 2008. Retrieved July 7, 2008.  ^ Weiss, Rick Weiss (9 September 2007). "Radio Telescope And Its Budget Hang in the Balance". The Washington Post. Arecibo, Puerto Rico: The Washington Post
The Washington Post
Company. p. A01. Retrieved July 8, 2008. The cash crunch stems from an NSF senior review completed last November. Its $200 million astronomy division, increasingly committed to ambitious new projects, but long hobbled by flat Congressional budgets, was facing a deficit of at least $30 million by 2010.  ^ a b "Areciboscience.org". Areciboscience.org. Retrieved May 11, 2012.  ^ Liz Arelis Cruz Maisonave. "Buscan frenar cierre de Radiotelescopio en Arecibo". El Vocero
El Vocero
(in Spanish). Retrieved September 4, 2008. [permanent dead link] ^ "Senado aprueba emisión de bonos de $450 millones" (in Spanish). Primera Hora. November 14, 2007. Archived from the original on December 8, 2008. Retrieved September 4, 2008.  ^ Gerardo, E.; Alvarado, León (August 10, 2008). Gobernador firma emisión de bonos. El Nuevo Día.  ^ Serrano, José E. (September 19, 2007). "Serrano concerned about potential Arecibo closure". serrano.house.gov. Archived from the original on July 30, 2008. Retrieved 2008-09-04.  ^ "Congress gets bill to save Arecibo Observatory". Cornell University. 3 October 2007. Archived from the original on October 8, 2007. Retrieved September 4, 2008.  ^ Jeannette Rivera-lyles (April 25, 2008). "Clinton turns attention to observatory in Puerto Rico". Orlando Sentinel. Archived from the original on September 30, 2008. Retrieved September 4, 2008.  ^ " Observatory
Donations site".  ^ "Dear Colleague Letter: Providing Progress Update on Senior Review Recommendations" (Press release). The National Science Foundation. September 20, 2007. Archived from the original on June 28, 2008. Retrieved July 9, 2008.  ^ Arecibo participated in 90 of the 111 asteroid radar observations in 2005–2007. See JPL's list of all asteroid radar observations. ^ Chang, K., "A Hazy Future for a 'Jewel' of Space Instruments.", New York Times, November 20, 2007 ^ Jacqui Goddard, "Threat to world's most powerful radio telescope means we may not hear ET", Daily Telegraph, July 12, 2008 ^ "Save Arecibo: Write to Congress". Retrieved July 19, 2008 ^ "12-m Phase Reference Antenna". Naic.edu. June 28, 2010. Archived from the original on March 15, 2012. Retrieved May 11, 2012.  ^ "FY 2010
Budget Request to Congress". Retrieved May 26, 2009 ^ a b "Major multi-user research facilities" p. 35–38. Retrieved 2010
Feb. 10 ^ " NASA
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SRI International
to manage Arecibo Observatory". Cornell Chronicle. June 3, 2011. Retrieved January 11, 2012.  ^ "Management and Operation of the NAIC" retrieved 2013 Apr 6 ^ "Dear Colleague Letter: Concepts for Future Operation of the Arecibo Observatory". 26 October 2015. Retrieved November 11, 2015.  ^ "Dear Colleague Letter: Intent to Release a Solicitation Regarding Future Continued Operations of the Arecibo Observatory". September 30, 2016. Retrieved October 2, 2016.  ^ Clery, Daniel (September 26, 2017). "Hurricane damage threatens Arecibo Observatory's future". Science. doi:10.1126/science.aaq0598. (Subscription required (help)).  ^ Clery, Daniel (March 2, 2018). "Arecibo telescope saved by university consortium". Science. 359 (6379): 965–966. (Subscription required (help)).  ^ Visitor Center information Archived November 4, 2013, at the Wayback Machine. ^ "Sociedad de Astronomia del Caribe". www.sociedadastronomia.com.  ^ "3,273,156 (1966-09-13) Helias Doundoulakis, Radio Telescope having a scanning feed supported by a cable suspension over a stationary reflector". U.S. Patent Office. 

Further reading[edit]

Friedlander, Blaine P. Jr. (November 14, 1997). "Research rockets, including an experiment from Cornell, are scheduled for launch into the ionosphere next year from Puerto Rico". Cornell University. Archived from the original on November 19, 2005.  Ruiz, Carmelo (1998-03-03). "Activists protest US Navy radar project". Global Network Against Weapons and Nuclear Power in Space. Archived from the original on 2001-05-01.  Amir Alexander (July 3, 2008). "Budget Cuts Threaten Arecibo Observatory". The Planetary Society. Archived from the original on July 21, 2008.  Blaine Friedlander (June 10, 2008). "Arecibo joins global network to create 6,000-mile (9,700 km) telescope". EurekAlert.  Lauren Gold (June 5, 2008). "Clintons (minus Hillary) visit Arecibo; former president urges more federal funding for basic sciences". Cornell university.  Henry Fountain (December 25, 2007). "Arecibo Radio Telescope Is Back in Business After 6-Month Spruce-Up". New York Times.  Entry into the National Register of Historic Places Cohen, Marshall H. (2009). "Genesis of the 1000-foot Arecibo Dish". Journal of Astronomical History and Heritage. 12: 141–152. Bibcode:2009JAHH...12..141C.  Altschuler, Daniel R.; Salter, Christopher J. (2013). "The Arecibo Observatory: Fifty astronomical years". Physics Today. 66 (11): 43. Bibcode:2013PhT....66k..43A. doi:10.1063/PT.3.2179. 

External links[edit]

Wikimedia Commons has media related to Arecibo Observatory.

Official website Arecibo Planetary Radar Arecibo Science Advocacy Partnership Ángel Ramos Foundation Visitor Center SETI@home IEEE
History Center – IEEE
Milestones: NAIC/Arecibo Radiotelescope Lofar The Arecibo Observatory
Contributions Site Letter to save Arecibo Observatory

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Radio astronomy


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Radio telescopes (List)

Individual telescopes

Radio Telescope (Russia) 500 m Aperture Spherical
Telescope (FAST, China) Arecibo Observatory
(Puerto Rico, US) Caltech Submillimeter Observatory
(CSO, US) Effelsberg Telescope (Germany) Large Millimeter Telescope
Large Millimeter Telescope
(Mexico) Yevpatoria RT-70 (Ukraine) Galenki RT-70 (Russia) Suffa RT-70 (Uzbekistan) Green Bank Telescope
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Lovell Telescope
(UK) Ooty Telescope (India) UTR-2 decameter radio telescope (Ukraine) Sardinia Radio Telescope
Sardinia Radio Telescope
(Italy) Usuda Telescope (Japan) Qitai Radio Telescope
Qitai Radio Telescope

Southern Hemisphere HartRAO (South Africa) Parkes Observatory
(Australia) Warkworth Radio Astronomical Observatory


Allen Telescope Array
Allen Telescope Array
(ATA, California, US) Atacama Large Millimeter Array
Atacama Large Millimeter Array
(ALMA, Chile) Australia Telescope Compact Array
Australia Telescope Compact Array
(ATCA, Australia) Australian Square Kilometre Array Pathfinder
Australian Square Kilometre Array Pathfinder
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Canadian Hydrogen Intensity Mapping Experiment
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European VLBI Network
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Event Horizon Telescope
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Green Bank Interferometer
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Giant Metrewave Radio Telescope
(GMRT, India) Korean VLBI Network
Korean VLBI Network
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Large Latin American Millimeter Array
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Murchison Widefield Array
(MWA, Australia) Multi-Element Radio Linked Interferometer Network (MERLIN, UK) Molonglo Observatory
Synthesis Telescope (MOST, Australia) Northern Cross Radio Telescope
Northern Cross Radio Telescope
(Italy) Northern Extended Millimeter Array
Northern Extended Millimeter Array
(France) One-Mile Telescope
One-Mile Telescope
(UK) Primeval Structure Telescope
Primeval Structure Telescope
(PaST, China) Square Kilometre Array
Square Kilometre Array
(SKA, Australia, South Africa) Submillimeter Array
Submillimeter Array
(SMA, US) Very Large Array
Very Large Array
(VLA, New Mexico, US) Very Long Baseline Array
Very Long Baseline Array
(VLBA, US) Westerbork Synthesis Radio Telescope
Westerbork Synthesis Radio Telescope
(WSRT, Netherlands)

Space-based telescopes

(Russia) HALCA (Japan)


Algonquin Radio Observatory
(Canada) Haystack Observatory
(US) Jodrell Bank Observatory
(UK) Mullard Radio Astronomy
(UK) National Radio Astronomy
(US) Onsala Space Observatory
(Sweden) Special
Astrophysical Observatory
of the Russian Academy of Science (SAORAS, Russia) Warkworth Radio Astronomical Observatory Pushchino Radio Astronomy
(PRAO ASC LPI, Russia)


PARL (Canada) DRAO (Canada) ESA New Norcia (Australia)


Elizabeth Alexander John G. Bolton Edward George Bowen Ronald Bracewell Jocelyn Bell Burnell Arthur Covington Frank Drake Antony Hewish Karl Guthe Jansky (Unit: jansky) Kenneth Kellermann Frank J. Kerr John D. Kraus Bernard Lovell Jan Oort Joseph Lade Pawsey Ruby Payne-Scott Arno Penzias Govind Swarup Grote Reber Martin Ryle Gart Westerhout Paul Wild Robert Wilson

Related articles

Cosmic microwave background radiation SETI Interferometry Radio propagation Aperture synthesis Wow! signal Radio signal from HD 164595 Pulsar
timing array

Optical astronomy Submillimetre astronomy Infrared astronomy High-energy astronomy Gravitational-wave astronomy

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U.S. National Register of Historic Places


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Extraterrestrial life

Events and objects

ALH84001 Cells in the stratosphere CI1 fossils Murchison meteorite Nakhla meteorite Polonnaruwa meteorite Red rain in Kerala Shergotty meteorite Viking lander biological experiments Yamato 000593

Signals of interest

CP 1919 (misidentified pulsar) CTA-102 (misidentified quasar) Fast radio burst (unknown origin) Wow! signal
Wow! signal
(inconclusive) KIC 8462852
KIC 8462852
(unusual light fluctuations) SHGb02+14a (radio source) HD 164595
HD 164595
signal (unknown origin)

Life in the Universe

Earliest known life forms Life on Enceladus Life on Europa Life on Mars Life on Titan Life on Venus

Planetary habitability

Catalog of Nearby Habitable Systems Circumstellar habitable zone Earth analog Extraterrestrial liquid water Galactic habitable zone Habitability of binary star systems Habitability of orange dwarf systems Habitability of red dwarf systems Natural satellite habitability Planetary habitability

Space missions

Beagle 2 Biological Oxidant and Life Detection BioSentinel Curiosity Darwin Enceladus Explorer Enceladus Life Finder Europa Clipper ExoMars ExoLance EXPOSE Foton-M3 Icebreaker Life Journey to Enceladus and Titan Laplace-P Life Investigation For Enceladus Living Interplanetary Flight Experiment Mars Geyser Hopper Mars sample return mission Mars 2020 Northern Light Opportunity SpaceX Red Dragon Spirit Tanpopo Titan Mare Explorer Venus In Situ Explorer Viking 1 Viking 2

Interstellar communication

Active SETI Allen Telescope Array Arecibo message Arecibo Observatory Berkeley SETI
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Breakthrough Listen Breakthrough Message

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The Science of Aliens


Ancient astronauts Aestivation hypothesis Aurelia and Blue Moon Cosmic pluralism Directed panspermia Drake equation Extraterrestrial hypothesis Fermi paradox Great Filter Hypothetical types of biochemistry Interplanetary contamination Kardashev scale Mediocrity principle Neocatastrophism Panspermia Planetarium hypothesis Rare Earth hypothesis Zoo hypothesis

Related topics

Astrobiology Astroecology Biosignature Rejection of Earth-based abiogenesis (Fred Hoyle) Brookings Report Planetary protection Potential cultural impact of extraterrestrial contact Exotheology Extraterrestrials in fiction Extremophile Nexus for Exoplanet
System Science Noogenesis San Marino Scale Technosignature UFO religi