Cerro Tololo Interamerican Observatory (CTIO)
The Cerro Tololo Inter-American Observatory (CTIO) is located about 500 kilometers north of Santiago, Chile, about 70 kilometers east of La Serena, at an altitude of 2200 meters. CTIO operates the 4-meter Blanco telescope on Cerro Tololo, and the 4.1-meter SOAR Telescope, on Cerro Pachon, next to the 8-meter Gemini Telescope. CTIO is a division of NOAO.

Gemini Observatory
The Gemini Observatory consists of twin, 8.1-meter-diameter optical/infrared telescopes located on two of the best observing sites on the planet. From their locations on mountains in Hawaii and Chile, Gemini's telescopes can collectively access the entire sky. Gemini was built and is operated by a partnership of seven countries including the United States, United Kingdom, Canada, Chile, Australia, Brazil and Argentina.

National Astronomy and Ionosphere Center (NAIC) / Arecibo Observatory
The National Astronomy and Ionosphere Center (NAIC) provides world-class observational facilities for research in radio astronomy, solar system radar astronomy, and studies of the upper atmosphere and ionosphere. Operated by Cornell University, the Center's cornerstone research instrument is a 305-meter (1000-ft) diameter radio telescope, located at the Arecibo Observatory approximately ten miles inland from the city of Arecibo, Puerto Rico. As the world's largest single-dish radio telescope and most powerful scientific radar system, Arecibo Observatory is unique in its sensitivity and in the diversity of the scientific user community that it serves.

National Radio Astronomy Observatory (NRAO)
The National Radio Astronomy Observatory (NRAO) operates a complementary suite of powerful telescopes for exploring the universe: the Robert C. Byrd Green Bank Telescope (GBT), the world's most sensitive single-dish radio telescope; the Very Large Array (VLA), an array of 27 radio telescopes that is among the most productive research tools in astronomy; and the Very Long Baseline Array (VLBA), an array of 10 radio telescopes and the highest- resolution astronomical telescope. NRAO is also building two new major facilities that will significantly enhance astronomers' research capabilities and open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA) and the Expanded Very Large Array (EVLA). Detection of the radio waves emitted by astronomical objects demands technology and signal processing that push the state-of-the-art.

National Optical Astronomy Observatory (NOAO)
The National Optical Astronomy Observatory (NOAO) is the United States’ national research and development center for ground-based nighttime astronomy. In particular, NOAO is enabling the development of the U.S. optical-infrared (O/IR) system, an alliance of public and private observatories allied for excellence in scientific research, education and public outreach.  Its telescopes range in aperture size from 2-meter to 10-meters. NOAO is participating in the development of telescopes with aperture sizes of 20-meters and larger as well as a unique 8-meter telescope that will make a 10-year movie of the southern sky.

National Solar Observatory (NSO)
The National Solar Observatory (NSO) seeks to advance knowledge of the sun, both as an astronomical object and as the dominant external influence on Earth, by providing forefront observational opportunities to the research community. NSO has two observing facility locations: in Kitt Peak, Ariz., home of Synoptic Optical Long-term Investigations of the Sun (SOLIS) and the McMath-Pierce Telescope; and Sacramento Peak, N.M., where the Dunn Solar Telescope, Evans Solar Facility and Hilltop Dome Facility are located. The next generation of ground-based solar telescope, the Advanced Technology Solar Telescope (ATST), is now in the design phase by a collaboration of 22 institutions and a broad segment of the solar physics community.