The ARECIBO OBSERVATORY is a radio telescope in the municipality of
Puerto Rico . This observatory is operated by SRI
International , USRA and UMET , under cooperative agreement with the
National Science Foundation
National Science Foundation (NSF) . The observatory is the sole
facility of the National
Ionosphere Center (NAIC), which
refers to the observatory, and the staff that operates it. From its
construction in the 1960s until 2011, the observatory was managed by
Cornell University .
The observatory's 1,000-foot (305-metre) radio telescope was the
largest single-aperture telescope from its completion in 1963 until
July 2016 when the Five hundred meter Aperture
(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. It was the
featured listing in the
National Park Service
National Park Service 's weekly list of
October 3, 2008. The center was named an IEEE Milestone in 2001. It
has a visitor center that is open part-time.
* 1 General information
* 2 Design and architecture
* 3 Research and discoveries
* 4 SETI, METI
* 4.1 The
* 4.2 The
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
The main collecting dish is 305 m (1,000 ft) in diameter, constructed
inside the depression left by a karst sinkhole . The dish surface is
made of 38,778 perforated aluminum panels, each about 3 by 6 feet (1
by 2 m), supported by a mesh of steel cables. The ground beneath is
accessible and supports shade-tolerant vegetation.
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. 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
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
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).
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.
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.
The observatory was built between mid-1960 and November 1963 and
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 that offered perfect cavities for
a very large dish. 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 "> The
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. In 1968, the
discovery of the periodicity of the
Crab Pulsar (33 milliseconds) by
Lovelace and others provided the first solid evidence that neutron
stars exist. In 1974, Hulse and Taylor discovered the first binary
PSR B1913+16 , 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. 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 . The following year, Polish
Aleksander Wolszczan made the discovery of pulsar PSR
B1257+12 , which later led him to discover its three orbiting planets.
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 .
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 .
2010 to February 2011, American astronomers Matthew
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
THE 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. 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.
THE 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
SETI and Active
Search for Extra-Terrestrial Intelligence (SETI) is a program to
search for extraterrestrial life or advanced technologies.
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
SETI Institute 's Project Phoenix observations. The Einstein@Home
distributed computing project has found more than 20 pulsars in
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
Limited amateur radio operations have occurred, using moon bounce or
Earth–Moon–Earth communication , in which radio signals aimed at
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. 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.
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. Between 2001 and 2006, NASA
decreased, then eliminated, its support of the planetary radar, 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. 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
Observatory research and to publicize its accomplishments in
astronomy, aeronomy and planetary radar. 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
Contributions by the government of
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
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.
The bond authorization, with a $3.0 million appropriation, was
approved by the Senate of
Puerto Rico on November 14, 2007, on the
first day of a special session called by
Aníbal Acevedo Vilá . The
Puerto Rico House of Representatives repeated this action on June 30,
2008. Puerto Rico's governor signed the measure into law in August
2008. These funds were made available during the second half of 2009.
In a letter published on September 19, 2007,
José Enrique Serrano
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
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
Resident Commissioner ,
Luis Fortuño , along with Dana
Rohrabacher , filed legislation to assure the continued operation of
the famed observatory. A similar bill was filed in the
U.S. Senate in
April 2008 by the Junior Senator from New York,
Hillary Clinton .
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 and Universidad Metropolitana ,
can accept contributions on behalf of the Arecibo Observatory.
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. 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
In November 2007,
The Planetary Society urged the
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 . 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. In July 2008, the
The Daily Telegraph
The Daily Telegraph reported that the funding
crisis, due to federal budget cuts, was still very much alive.
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
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. This allotment was an increase of about
30 percent over the FY-2009 budget. However, the FY-
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.
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. 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
NASA increased its support to $3.5 million per year in 2012.
2010 the NSF issued a call for new proposals for the
management of NAIC starting in FY-2012. On May 12, 2011, the agency
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. Upon the award of the new cooperative
agreement for NAIC management and operation, NSF also decertified NAIC
Federally Funded Research and Development Center (FFRDC) , 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
In October 2015, the NSF released a "Dear Colleague Letter"
reiterating its desire for a "substantially reduced funding commitment
On 2016 September 30, the NSF released a followup to the October 2015
"Dear Colleague Letter" announcing a solicitation for future operation
Observatory stating "The subject Solicitation will request the
submission of formal proposals involving the continued operation of
Observatory under conditions of a substantially reduced
funding commitment from NSF."
ÁNGEL RAMOS FOUNDATION VISITOR CENTER
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 . 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,
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
* 1960–1965, Dr.
William E. Gordon
William E. Gordon (Ph.D.,
Cornell University )
* 1965–1966, Dr. John W. Findlay (Ph.D.,
University of Cambridge
University of Cambridge )
* 1966–1968, Dr.
Frank Drake (Ph.D.,
Harvard University )
* 1968–1971, Dr.
Gordon Pettengill (Ph.D.,
UC Berkeley )
* 1971–1973, Dr.
Tor Hagfors (Ph.D.,
University of Oslo
University of Oslo )
* 1973–1982, Dr. Harold D. Craft Jr. (Ph.D.,
Cornell University )
* 1982–1987, Dr.
Donald B. Campbell (Ph.D.,
Cornell University )
* 1987–1988, Dr.
Riccardo Giovanelli (Ph.D., University of Bologna
* 1988–1992, Dr. Michael M. Davis (Ph.D.,
Leiden University )
* 1992–2003, Dr. Daniel R. Altschuler (es) (Ph.D., Brandeis
* 2003–2006, Dr. Sixto A. González (Ph.D., Utah State University
* 2006–2007, Dr. Timothy L. Hankins (Ph.D., University of
California at San Diego )
* 2007–2008, Dr. Robert B. Kerr (Ph.D.,
University of Michigan
University of Michigan )
* 2008–2011, Dr. Michael C. Nolan (Ph.D.,
University of Arizona
University of Arizona )
* 2011–2015, Dr. Robert B. Kerr (Ph.D.,
University of Michigan
University of Michigan )
* 2016–present Francisco Córdova
IN POPULAR CULTURE
* 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
James Bond movie
GoldenEye (1995), and as a level in the
Nintendo 64 video game
GoldenEye 007 .
* The film Contact (1997), based on the
Carl Sagan 1985 novel of the
same name, features the main character using the observatory as part
Fox Mulder went to the observatory in
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 novel Rollback,
Mary Doria Russell novel The Sparrow (1996) and the film The
* A radio telescope based on the observatory is featured in the
Just Cause 2
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
Battlefield 4 multiplayer map, Rogue Transmission, is inspired
by the observatory.
* The movie of
The Losers has one scene filmed in the observatory.
Puerto Rico portal
Air Force Research Laboratory
Air Force Research Laboratory
Atacama Large Millimeter Array (Chile)
Five hundred meter Aperture Spherical Telescope (China)
List of radio telescopes
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
William E. Gordon , founder and first director of the observatory
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