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Arecibo Observatory

The concept of the Arecibo telescope was first developed by Cornell Engineering Professor Bill Gordon in 1958, and construction began in the spring of 1960. The purpose of this Incoherent Scatter Radar was to study the ionosphere. It became operational in 1963. It is the largest single dish radio telescope in the world. Its main use is the research in atmospheric science, astronomy and planetary science.

The potential of the Arecibo Observatory, for radio and radar astronomy, was recognized by Professor Tommy Gold. Cornell University invested in faculty appointments in astronomy to fulfill the promise of these new research opportunities. Cornell University managed the Arecibo observatory since the beginning, first under a cooperative agreement with ARPA, then under a cooperative agreement with NSF.

The Arecibo Observatory is in Puerto Rico because all great astronomy observatories are near the equator, where earth rotations allow access to all parts of the sky. Polar locations allow access to only ½ of the sky. The karst topography in the area provides large natural sinkholes, minimizing excavation costs and providing natural support for a large, circular reflector. Karst terrain surrounding the reflector also provides natural protection from radio frequency interference. In addition, the tropical latitude provides overhead access to objects in the ecliptic plane and for radar studies of planets and asteroids.

One of the main parts of the Arecibo Observatory is the 430 antenna.  The antenna is 96 ft. in length; it receives and transmits radio waves of 430 MHz. This antenna is the Main instrument used to study the ionosphere.

The Arecibo Observatory is now nearly 50 years old, but the Telescope and nested instrumentation are not. Some of the recent upgrades include:

  • Passive optical instruments for study of the upper atmosphere began to be added in 1965.
  • Surface upgrade completed in 1973 that allowed frequency response to 2 GHz.
  • “S-band” 2380 MHz (13 cm) transmitter added in 1973 permits radar studies of planet surfaces.
  • High power lasers (“LIDAR”) added for studies of the middle and upper atmosphere in 1995.
  • Major upgrade completed in 1997 that converted line focus of the spherical reflector to a point focus, using “Gregorian optics”.
  • Ground-screen added in 1997 lowers edge spillover losses and reduces RFI reflection from the surrounding mountains.
  • “S-band” transmitter upgraded to a 1 MW system in 1997.
  • Visitor Center outreach and education facility added in 1997.
  • A radio “camera” permitting broad sky coverage and imaging completed in 2004.
  • A high frequency transmitter and mesh antenna that was later added in 2008 for active plasma experiments in the Earth’s ionosphere.

The Gregorian Dome houses the secondary and tertiary reflectors. It provides frequency coverage between 300 and 10,000 MHz. It also has the radar transmitter used to study planets, asteroids, and comets. Another upgrade added in 2004 was the ALFA Camera. Its surveys started in February 2005. Some of the details of this camera are:

  • 7 beams x 2 pol (linear) = 14 “pixels”
  • 1225-1525 MHz full range
  • Unmatched sensitivity (SEFD = 2.4 to 3 Jy)
  • 3.3’ x 3.8’ beams on 11’ X 13’ ellipse
  • Unprecedented capability for mapping the sky
  • Survey consortia self-organized by community

One of the historic projects in the Arecibo Observatory was The Binary Pulsar. In 1974, Russ Hulse and Joe Taylor discovered the binary motion of PSR 1916+13 revealing evidence that the system is losing energy by the emission of gravitational radiation, just as predicted by Einstein’s theory of General Relativity. In 1993, Hulse and Taylor received the Nobel Prize in physics for “the discovery of a new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation.”

The binary pulsar was used in the research for the first ExtraSolar Planets. In 1992, Alex Wolszczan and Dale Frail used precise pulsar timing measurements to detect the first ExtraSolar planetary system. The pulsar’s motion can be explained by the presence of at least 3 planets in tight orbit around the pulsar. The 1996, the Beatrice Tinsley Prize of the American Astronomical Society was awarded to Wolszczan for his precision timing of the pulsar planets. In 2004, Jean-Luc Margot was awarded the Harold C. Urey Prize by the Division of Planetary Sciences of the American Astronomical Society for his studies on binary asteroids and on planetary spin states.

The Arecibo Observatory has many optical instruments at its disposal including:

  • Three Fabry-Perot Interferometers
  •  One Ebert-Fastie Spectrophotometer
  •  Two Tilting-Filter Photometers
  •  Nd:YAG Doppler Rayleigh Lidar
  •  Alexandrite Doppler Resonance Lidar
  •  Two Dye-lasers (Resonance Lidars)

SRI International (SRI) teams with the Universities Space Research Association (USRA) and Universidad Metropolitana (UMET), have formed the Arecibo Management Partners (AMP) to chart a bold new vision for the future of the AO. AMP will operate on-site at AO as one organization, streamlining operations, eliminating remote management, improving communications between AO management and stakeholders, and enhancing staff morale. UMET, a member of Puerto Rico’s second largest private university system, AGMUS, will bring expertise in education public outreach, and facilities management.

UMET’s substantial infrastructure and personnel will provide transformational economies of scale, giving AO access to previously impossible levels of physical and staff resources. UMET’s large employee base and extensive on-island resources provide new career paths and employment opportunities for new and existing AO staff.
Twenty-seven supporting institutions (SIs) will collaborate with AMP to advance a common vision of Arecibo’s bright future in science and education. In addition to these academic institutions, AMP enjoys the expressed support of the Puerto Rico Department of Education and two PR economic development agencies, the Puerto Rico Industrial Development Company (PRIDCO) and the Department of Tourism, all keenly interested in integrating the AO into the local economic development.

The AO is a vital resource to the astronomy, planetary science, and space science communities through an ambitious facility development plan made possible by vigorous pursuit of funding opportunities with our collaborators. Our Supporting Institutions (SIs) provide broad technical, equipment, and logistic resources to AO’s science and education missions. They expand the AO user base and create staffing resources and professional development opportunities for AO staff.

AMP’s AST plan raises the AO’s visibility and stature within the community to a level befitting its scientific legacy. With unparalleled telescope sensitivity enhanced by new development in receivers and data acquisition systems, the re-invigorated AO delivers science endorsed by the Decadal Survey process: gravitational-wave astronomy through pulsar timing, studies of cosmic structure formation and Galactic energetics through neutral-hydrogen surveys and molecular-line spectroscopy, and probes of star formation and collapse through Very Long Baseline Interferometry (VLBI). The PRS plan expands the AO’s invaluable characterization of near-Earth object orbits and physical properties, for mitigation of both potential impact hazards and risks to future robotic and crewed missions. PRS also maps planets and satellites to uncover surface features, sub-surface geologies, and interior structures.

The new AO management plan weaves the AO into the fabric of scientific, educational, and economic development in PR, with mutual benefits for the AO, SIs, scientific stakeholders, and the people of Puerto Rico. It will institute a program to brink 42,000 K-12 students to AO for tours and workshops emphasizing STEM education, create a summer research academy for high school students, train 20 STEM high school teachers a year, maintain the outstanding REU program, create undergraduate intern positions in all aspects of the AO operations, and, for the first time, creates PhD opportunities for Hispanic students with our CONUS and international SIs. The outreach plan updates the Angel Ramos Foundation Visitor Center, expanding the visitor experience with tours of the entire site. Virtual tours of space and the AO will be developed on an interactive video gaming platform for distribution worldwide.