Arecibo Observatory.


At the Arecibo Observatory we are always looking for ways to improve our connections and collaborations; and we are excited about our new site which includes a redesigned look, changes to navigation and updated information on our Science and Visitor’s Center. So take a look around and enjoy! We hope you find it entertaining and informative. I also encourage you to visit us in person, our state of the art Science and Visitor’s Center blends Arecibo’s scientific accomplishments with current technology to provide a user experience like no other. We hope to see you soon!

- Francisco Cordova, MSCE, PE
Director of the Arecibo Observatory

Recent Posts

Arecibo Planetary Radar Returns to Action with Images of Asteroid Phaethon

Phaethon - Figure 1
Planetary December 22, 2017

Columbia, MD and Puerto Rico: After several months of downtime in the aftermath of Hurricane Maria, the Arecibo Observatory Planetary Radar returned to normal operation providing the best images to date of near-Earth asteroid 3200 Phaethon, which is thought to be the parent body for the Geminids meteor shower. Radar images reveal Phaethon to be roughly spherical with a diameter of about 6 km (3.6 mi), roughly 1 km (0.6 mi) larger than previous estimates. Read More

First Asteroid Detection since Hurricane Maria   December 12, 2017

Radar Observations and Shape Model of Asteroid 16 Psyche   Jul 21, 2017

Arecibo refines our knowledge of a potentially hazardous asteroid  Apr 17, 2017

Arecibo Observatory captures revealing images of Comet 45P/Honda-Mrkos-Pajdusakova   Feb 12, 2017

Discovery Announcement of Binary System (163693) Atira   Jan 20-23, 2017

Asteroids by the AO Planetary Radar Group

Astronomers peer into the lair of a mysterious source of cosmic radio bursts

Pulsar Astronomy Jan 10, 2018

Using the Arecibo Observatory in Puerto Rico and the Green Bank Telescope in West Virginia, a team from Universities Space Research Association (USRA) and other institutions today announced today at the American Astronomical Society’s winterAAS meeting that mysterious bursts of radio emission, called Fast Radio Bursts (FRB), may be coming from near a giant black hole. Read More

Why are Quasars so Bright?  JULY 18, 2017

The Mystery of Part Time Pulsars  JULY 18, 2017

Gaia Weighs in on the Pleiades Distance Controversy  Jan 27, 2017

Arecibo Puts Limits on Gravitational Wave Models   Jan 20, 2017

Arecibo Call for Ionospheric Modification (HF facility)

Space & Atmospheric Jul 21, 2017

The Arecibo Observatory invites you to submit proposals for the use of the HF facility during 2018. HF experiments at Arecibo are scheduled by demand in periods of 5-7 days around new moon. Proposals should specify the associated diagnostics required: the incoherent scatter radar (ISR), active and passive optical instruments and others. Read More

Mid-latitude Radio-Frequency Auroras   Jul 21, 2017

Nighttime plasma lines are measured at Arecibo (Vierinen et al. [2017]).  Jun 15, 2017

The sensitivity of the Arecibo Observatory made possible to observe Gyrolines 

Creating space plasma from the ground  Jan 14, 2017


Why is it so special?

This giant telescope has scrutinized our atmosphere from a few kilometers to a thousand kilometers where it smoothly connects with interplanetary space. With its radar vision it studies the properties of planets, comets and asteroids. In our Galaxy it detects the faint pulses emitted hundreds of times per second from pulsars. And from the farthest reaches of the Universe quasars and galaxies emit radio waves which arrive at earth 100 million years later as signals so weak that they can only be detected by a giant eye like this one.

Planetary Radar

The Observatory’s planetary radar is a uniquely powerful instrument for the characterization and orbital refinement of NEO’s. The Arecibo Telescope has collected data on Mercury, Venus, Jovian Satellites, Saturn’s Rings and satellites, numerous asteroids and comets


The Arecibo Observatory Radio Telescope provide alternative views to optical telescopes. It can detect invisible gas and and can reveal areas of space that may be obscured with cosmic dust.


The Observatory’s incoherent scatter radar, combined with its extensive suite of optical LIDAR and airglow instrumentation provide a unique capability for studies of the earth’s upper atmosphere.

Education & Outreach

The newly refurbished and extended Science & Visitor Center, modernized exhibition space and state-of-the-art auditorium welcome nearly 100,000 visitors a year and support STEM education at all levels throughout Puerto Rico and Beyond.

Our telescope

The Vision

Toward 2025 the Arecibo Observatory (AO) will continue to be recognized as a world-leading radio astronomy, solar system radar and atmospheric physics facility, contributing highly relevant data to support discovery, innovation and the advancement of science for the well-being of human kind. AO will establish a world-class on-site and virtual educational program supporting K-16 and PhD-level studies, to stimulate and promote new generations of scientists and engineers at national level, while also contributing to the economic and social development of Puerto Rico.

"If you dream, have big dreams and have talented supporters to help you”

William "Bill" Gordon

Arecibo Observatory

Recent Discoveries