Date Dedicated
2001-11-01
Dedication #
41
Location
Arecibo, Puerto Rico
IEEE Regions
9
IEEE sections
Puerto Rico & Caribbean
IEEE Milestone and ASME Landmark
Achievement date range
1963

Arecibo, Puerto Rico, November 2001, IEEE Puerto Rico & Caribbean Section

(IEEE Milestone and ASME Landmark

The Arecibo Observatory, the world's largest radiotelescope, was dedicated in 1963. Its design and implementation led to advances in the electrical engineering areas of antenna design, signal processing, and electronic instrumentation, and in the mechanical engineering areas of antenna suspension and drive systems. The drive system positions all active parts of the antenna with millimeter precision, regardless of temperature changes, enabling the telescope to maintain an accurate focus. Its subsequent operation led to advances in the scientific fields of radioastronomy, planetary studies, and space and atmospheric sciences.

The plaque is in the visitors' center at the Arecibo observatory, approximately 20 km south of Arecibo, Puerto Rico, at the end of road 625. However, because of the recent announcement by the National Science Foundation that the Arecibo observatory will be decommissioned, the visitors' center might be closed. Our understanding as of this writing (20 Nov. 2020) is that the plan is that the visitors' center will be preserved and reopened.

With the completion in 1997 of the $25 million Gregorian reflector system suspended 137 meters (450 feet) above the telescope's 305-meter (1 ,000-foot) diameter dish, together with the construction of a ground screen and powerful new radar transmitter, the Arecibo telescope remains unmatched in its sensitivity and versatility for radio studies of the atmosphere, the solar system, and the universe. ## Facts & Figures • Arecibo Observatory sits on a 48-hectare (118-acre) site outside of the city of Arecibo, Puerto Rico. There are 140 staff members at the site, and another fifteen at NAIC headquarters on the Cornell University campus in Ithaca, New York. • The observatory cost$9.3 million when it was completed in 1963. The 1974 upgrade cost another $9 million. The most recent upgrade completed in 1997, the addition of the Gregorian, a new radar transmitter, and ground screen cost$25 million. If the entire facility were to be built today, it would cost in excess of \$100 million.
• More than 8 kilometers (five miles) of 2.5 cm. (1-inch)-thick steel cables and approximately 40 kilometers (25 miles) of 0.6 cm. (quarter-inch)-thick cables support the reflector. They keep it from changing shape as temperatures fluctuate and winds blow.
• The dish, 305 meters (1,000 feet) across, has a surface area of eighteen acres, the equivalent of 26 football fields.
• An on-site plant processed 270,000 kg (300 tons) of aluminum to fabricate the perforated panels that form the spherical surface. There are 38,778 of them, each measuring 101 cm. x 203 cm. (40 x 80 inches).
• Arecibo's azimuth arm is 93 meters (304 feet) long, 3.7 meters (12 feet) wide, and 10 meters (33) feet deep. It rotates on a circular track 42.7 meters (140 feet) in diameter.
• There are three towers supporting the structure. One is 111 meters (365 feet) high, and the other two are each 81 meters (265 feet) high. All three tops are at the same elevation.
• The 363 kilometers (227 miles) of aluminum angle used to make the frames supporting the main reflector panels could have made a guardrail all the way around the island of Puerto Rico.
• The dome that houses the Gregorian reflectors is six stories high, is suspended 137 meters (450 feet) above the main reflector, and, although made of aluminum to minimize its weight, still weighs 68,000 kg (75 tons).