Arecibo Observatory
The Arecibo Telescope in 2019
Alternative namesNational Astronomy and Ionosphere Center Edit this at Wikidata
Named afterArecibo Edit this on Wikidata
Observatory code 251 Edit this on Wikidata
LocationArecibo, Puerto Rico, Caribbean
Coordinates18°20′39″N 66°45′10″W / 18.34417°N 66.75278°W / 18.34417; -66.75278
Altitude498 m (1,634 ft) Edit this at Wikidata Edit this at Wikidata
  Related media on Commons
National Astronomy and Ionosphere Center
Nearest cityArecibo
Area118 acres (48 ha)
ArchitectKavanagh, T. C.
Engineervon Seb, Inc., T. C. Kavanagh of Praeger-Kavanagh, and Severud-Elstad-Krueger Associates[1]
NRHP reference No.07000525
Added to NRHPSeptember 23, 2008[2]

The Arecibo Observatory, also known as the National Astronomy and Ionosphere Center (NAIC) and formerly known as the Arecibo Ionosphere Observatory, is an observatory in Barrio Esperanza, Arecibo, Puerto Rico owned by the US National Science Foundation (NSF).

The observatory's main instrument was the Arecibo Telescope, a 305 m (1,000 ft) spherical reflector dish built into a natural sinkhole, with a cable-mount steerable receiver and several radar transmitters for emitting signals mounted 150 m (492 ft) above the dish. Completed in 1963, it was the world's largest single-aperture telescope for 53 years, surpassed in July 2016 by the Five-hundred-meter Aperture Spherical Telescope (FAST) in China. Following two breaks in cables supporting the receiver platform in mid-2020, the NSF decommissioned the telescope. A full collapse of the telescope occurred on December 1, 2020, before either repairs or controlled demolition could be conducted. In 2022, the NSF announced the telescope will not be rebuilt, with an educational facility to be established on the site.

The observatory also includes a smaller radio telescope, a LIDAR facility, and a visitor center, which remained operational after the telescope's collapse.[3][4] The asteroid 4337 Arecibo is named after the observatory by Steven J. Ostro, in recognition of the observatory's contributions to the characterization of Solar System bodies.[5]


See also: History of the Arecibo Telescope

As part of the United States Department of Defense (DoD) Advanced Research Projects Agency (ARPA) missile defense program, ARPA had sought a means to try to detect incoming missiles while they traveled through the ionosphere. The Arecibo Telescope was funded as a means to study Earth's ionosphere for this purpose, and serving a dual-use as a general-purpose radio telescope. Construction of the telescope and its supporting facilities were started in September of 1960, with the telescope operational by 1963. The telescope and supporting observatory were formally opened as the Arecibo Ionospheric Observatory on November 1, 1963.[6]

Ownership of the observatory transferred from the DoD to the National Science Foundation on October 1, 1969. NSF named Cornell University to manage the observatory's functions. By September 1971, NSF renamed the observatory as the National Astronomy and Ionosphere Center (NAIC) and had made it a federally funded research and development center (FFRDC).[6] NASA began contributing towards funding of the observatory alongside NSF as to support its planetary radar mission.[7]

In the early 2000s, NASA started to reduce their contribution to the Arecibo Observatory, putting more pressure on NSF to continue to fund the facility.[8] In 2006, NSF made its first possible suggestion of significantly reducing its funding towards Arecibo and potentially decommissioning the observatory.[9] Academics and politicians lobbied to increase funding bookmarked for Arecibo to stave off its closure, and NASA recommitted funding in 2011 for study of near-earth objects.[10] To further cut losses, in 2011 NSF delisted Arecibo as a FFRDC, removed Cornell as the site operator, and replaced them with a collaborative team led by SRI International, which allowed the observatory to be able to offer its facilities to a wider range of projects.[11]

Damage to the telescope from Hurricane Maria in 2017 led NSF again to consider the possibility of decommissioning the observatory as the costs of maintaining it had become too great.[12] A consortium led by the University of Central Florida (UCF) stepped forward to offer to manage the observatory and cover a significant portion of the operations and maintenance costs, and in 2018, NSF made UCF's consortium the new site operators,[13][14] though no specific actions were announced.

After an auxiliary and main cable failure on the telescope in August and November 2020, respectively, the NSF announced the decision that they would decommission the telescope through controlled demolition, but that the other facilities on the observatory would remain operational in the future. Before the safe decommission of the telescope could occur, remaining support cables from one tower rapidly failed in the morning of December 1, 2020, causing the instrument platform to crash through the dish, shearing off the tops of the support towers, and partially damaging some of the other buildings, though there were no injuries.[15] NSF stated in 2020 that it was their intention to have the other observatory facilities operational as soon as possible and were looking at plans to rebuild a new telescope instrument in its place.[16] In 2022, the NSF announced the telescope will not be rebuilt, with an educational facility to be established on the site.[17] Cold Spring Harbor Laboratory in New York; the University of Maryland, Baltimore County; the University of Puerto Rico, Río Piedras Campus in San Juan; and the University of the Sacred Heart, also in San Juan were selected by NSF in 2023 to set up and run an education center called Arecibo C3 (Arecibo Center for Culturally Relevant and Inclusive Science Education, Computational Skills, and Community Engagement).[18]


Arecibo Telescope

Main article: Arecibo Telescope

The observatory's main feature was its large radio telescope, whose main collecting dish was an inverted spherical dome 1,000 feet (305 m) in diameter with an 869-foot (265 m) radius of curvature,[19] constructed inside a karst sinkhole.[20] The dish's surface was made of 38,778 perforated aluminum panels, each about 3 by 7 feet (1 by 2 m), supported by a mesh of steel cables.[19] The ground beneath supported shade-tolerant vegetation.[21]

Since its completion in November 1963, the Telescope had been used for radar astronomy and radio astronomy, and had been part of the Search for extraterrestrial intelligence (SETI) program. It was also used by NASA for Near-Earth object detection. Since around 2006, NSF funding support for the telescope had waned as the Foundation directed funds to newer instruments, though academics petitioned to the NSF and Congress to continue support for the telescope. Numerous hurricanes, including Hurricane Maria, had damaged parts of the telescope, straining the reduced budget.

Two cable breaks, one in August 2020 and a second in November 2020, threatened the structural integrity of the support structure for the suspended platform and damaged the dish. The NSF determined in November 2020 that it was safer to decommission the telescope rather than to try to repair it, but the telescope collapsed before a controlled demolition could be carried out. The remaining support cables from one tower failed around 7:56 a.m. local time on December 1, 2020, causing the receiver platform to fall into the dish and collapsing the telescope.[15][22]

NASA led an extensive failure investigation and reported the findings,[23] along with a technical bulletin with industry recommendations.[24] The investigation concluded that "a combination of low socket design margin and a high percentage of sustained loading revealed an unexpected vulnerability to zinc creep and environments, resulting in long-term cumulative damage and progressive zinc/wire failure".

Additional telescopes

The Arecibo Observatory also has other facilities beyond the main telescope, including a 12-meter (39 ft) radio telescope intended for very-long-baseline interferometry (VLBI) with the main telescope;[25] and a LIDAR facility[26] whose research has continued since the main telescope's collapse.

The Arecibo Radio Telescope as viewed from the observation deck, October 2013

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.[27] 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,[28] hosts a series of Astronomical Nights throughout the year, which feature diverse discussions regarding exoplanets, astronomical phenomena, and discoveries (such as Comet ISON). The purposes of the center are to increase public interest in astronomy, the observatory's research successes, and space endeavors.

List of directors

Source(s):[29][additional citation(s) needed]

See also


  1. ^ "Radio-Radar Telescope Will Probe Solar System". Electrical Engineering. 80 (7): 561. July 1961. doi:10.1109/EE.1961.6433355.
  2. ^ National Park Service (October 3, 2008). "Weekly List Actions". Archived from the original on March 29, 2013. Retrieved February 6, 2018.
  3. ^ "Arecibo Observatory Telescope Collapses, Ending An Era Of World-Class Research". Archived from the original on December 3, 2020. Retrieved December 3, 2020.
  4. ^ "Huge Puerto Rico radio telescope, already damaged, collapses". AP NEWS. December 1, 2020. Archived from the original on April 22, 2021. Retrieved December 3, 2020.
  5. ^ "(4337) Arecibo = 1933 HE = 1979 FR3 = 1979 HG2 = 1985 GB". Minor Planet Center. Archived from the original on October 4, 2016. Retrieved June 16, 2022.
  6. ^ a b Acevedo-Vila, Aníbal (October 30, 2003). "The 40th Anniversary of the Arecibo Observatory" (PDF). Congressional Record. Vol. 149, no. 156. p. E2181. Archived (PDF) from the original on August 21, 2021. Retrieved January 14, 2021.
  7. ^ 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.
  8. ^ Robert Roy Britt (December 20, 2001). "NASA Trims Arecibo Budget, Says Other Organizations Should Support Asteroid Watch". Imaginova. Archived from the original on December 5, 2008. Retrieved July 8, 2008.
  9. ^ Weiss, Rick Weiss (September 9, 2007). "Radio Telescope And Its Budget Hang in the Balance". The Washington Post. Arecibo, Puerto Rico. p. A01. Archived from the original on November 6, 2012. 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.
  10. ^ "NASA Support to Planetary Radar" Retrieved July 7, 2011
  11. ^ "Management and Operation of the NAIC" Archived March 3, 2018, at the Wayback Machine Retrieved April 6, 2013
  12. ^ Kaplan, Sarah (September 22, 2017). "Arecibo Observatory, Puerto Rico's famous telescope, is battered by Hurricane Maria". The Washington Post. Archived from the original on September 21, 2017. Retrieved September 24, 2017.
  13. ^ "Iconic Arecibo radio telescope saved by university consortium". Science. February 22, 2018. Archived from the original on March 4, 2018. Retrieved March 3, 2018.
  14. ^ "UCF-led Consortium to Manage Arecibo Observatory in Puerto Rico" (Press release). UCF Today. February 22, 2018. Archived from the original on April 19, 2018. Retrieved April 18, 2018.
  15. ^ a b "Giant Arecibo radio telescope collapses in Puerto Rico". The Guardian. Associated Press. December 1, 2020. Archived from the original on December 25, 2020. Retrieved December 1, 2020.
  16. ^ Grush, Loren (November 19, 2020). "Facing collapse, the famed Arecibo Observatory will be demolished". The Verge. Archived from the original on November 19, 2020. Retrieved November 19, 2020.
  17. ^ Witze, Alexandra (October 14, 2022). "Renowned Arecibo telescope won't be rebuilt — and astronomers are heartbroken". Nature. 610 (7933): 618–619. Bibcode:2022Natur.610..618W. doi:10.1038/d41586-022-03293-4. PMID 36241884. S2CID 252903742.
  18. ^ Oza, Anil (September 26, 2023). "A new era for Arecibo: legendary observatory begins next phase". Nature. 622 (7981): 19–20. Bibcode:2023Natur.622...19O. doi:10.1038/d41586-023-03021-6. PMID 37759120. S2CID 263113097. Archived from the original on September 28, 2023. Retrieved September 28, 2023.
  19. ^ a b Goldsmith, P. F.; Baker, L. A.; Davis, M. M.; Giovanelli, R. (1995). "Multi-feed Systems for the Arecibo Gregorian". Astronomical Society of the Pacific Conference Series. 75: 90–98. Bibcode:1995ASPC...75...90G.
  20. ^ "Telescope Description". National Astronomy and Ionosphere Center. Archived from the original on November 20, 2020. Retrieved November 20, 2020.
  21. ^ "Environmental Impact Statement for the Arecibo Observatory Arecibo, Puerto Rico (Draft)" (PDF). NSF. p. 66. Archived (PDF) from the original on December 16, 2020. Retrieved November 23, 2020. At the Arecibo Observatory, a mix of shade-tolerant species have colonized the area beneath the 305-meter radio telescope dish.
  22. ^ Coto, Danica (December 1, 2020). "Huge Puerto Rico radio telescope, already damaged, collapses". AP NEWS. Archived from the original on April 22, 2021. Retrieved December 5, 2020.
  23. ^ "Arecibo Observatory Auxiliary M4N Socket Termination Failure Investigation". NASA. June 30, 2021. Archived from the original on July 3, 2021. Retrieved July 1, 2021.
  24. ^ "NASA Engineering and Safety Center Technical Bulletin No. 21-05, Industry Recommendations from Arecibo Observatory Zinc Spelter Socket Joint Failure Analysis" (PDF). NASA. August 2, 2021. Archived (PDF) from the original on January 3, 2022.
  25. ^ Roshi, D. Anish; Anderson, L. D.; Araya, E.; Balser, D.; Brisken, W.; Brum, C.; Campbell, D.; Chatterjee, S.; Churchwell, E.; Condon, J.; Cordes, J.; Cordova, F.; Fernandez, Y.; Gago, J.; Ghosh, T.; Goldsmith, P. F.; Heiles, C.; Hickson, D.; Jeffs, B.; Jones, K. M.; Lautenbach, J.; Lewis, B. M.; Lynch, R. S.; Manoharan, P. K.; Marshall, S.; Minchin, R.; Palliyaguru, N. T.; Perera, B. B. P.; Perillat, P.; Pinilla-Alonso, N.; Pisano, D. J.; Quintero, L.; Raizada, S.; Ransom, S. M.; Fernandez-Rodriguez, F. O.; Salter, C. J.; Santos, P.; Sulzer, M.; Taylor, P. A.; Venditti, F. C. F.; Venkataraman, A.; Virkki, A. K.; Wolszczan, A.; Womack, M.; Zambrano-Marin, L. F. (July 13, 2019). "Astro2020 Activities and Projects White Paper: Arecibo Observatory in the Next Decade". arXiv:1907.06052 [astro-ph.IM].
  26. ^ "NSF begins planning for decommissioning of Arecibo Observatory's 305-meter telescope due to safety concerns [News Release 20-010]". Archived from the original on November 19, 2020. Retrieved November 19, 2020.
  27. ^ Visitor Center information Archived November 4, 2013, at the Wayback Machine
  28. ^ "Sociedad de Astronomia del Caribe". Archived from the original on May 5, 2014. Retrieved May 5, 2014.
  29. ^ Altschuler, Daniel; Salter, Chris (June 2014). "Early history of Arecibo Observatory". Physics Today. 67 (6): 12. Bibcode:2014PhT....67f..12A. doi:10.1063/PT.3.2402.
  30. ^ "Tor Hagfors, astronomy professor and Arecibo pioneer, dies at age 76". Cornell Chronicle. January 24, 2007. Archived from the original on November 20, 2020. Retrieved November 20, 2020.
  31. ^ Christiansen, Jen. "Pop Culture Pulsar: The Science Behind Joy Division's Unknown Pleasures Album Cover". Scientific American Blog Network. Archived from the original on November 12, 2020. Retrieved November 20, 2020.
  32. ^ a b Watson, Traci (November 2015). "Arecibo Observatory director quits after funding row". Nature. 527 (7577): 142–143. Bibcode:2015Natur.527..142W. doi:10.1038/nature.2015.18745. PMID 26560275.
  33. ^ "NSF announces over $5M in funding to create new STEM education and research center at the Arecibo Observatory site". September 25, 2023. Archived from the original on October 26, 2023. Retrieved October 26, 2023.

Further reading