From NOAO: “Milliarcsecond Astrophysics Through Open Access to the CHARA Array”

NOAO Banner

Doug Gies, Georgia State University



The Georgia State University Center for High Angular Resolution Astronomy (CHARA) Array at Mount Wilson Observatory is now open to investigators interested in exploring the universe at milliarcsecond resolution in the optical and near-infrared. A long-baseline interferometer, the CHARA Array offers the longest operating baselines in the world and enables diverse investigations, such as the measurement stellar angular diameters and shapes, and studies of orbiting companions and circumstellar environments. Community access to CHARA is funded by an NSF/MSIP award.

Located at Mount Wilson Observatory, the CHARA Array consists of six 1-m aperture telescopes arranged in a Y-shaped configuration with baselines ranging from 33 to 331 meters. By combining the light from these distributed telescopes, the angular resolution is equivalent to that of a single aperture telescope more than 300 meters in diameter, making it the highest angular resolution optical telescope in the world. A complement of six beam combiners offers interferometric capability in the wavelength range 0.5 to 2.5 microns. Multibeam combiners (up to six telescopes) support interferometric imaging studies. Depending on the spectral resolution and number of telescope beams feeding the combiner, the faint magnitude limit ranges from 5 to 9. However, these limits will undoubtedly improve with the introduction of adaptive optics now underway.

Open access to the Array will be phased in beginning in the 2017B observing semester, and some 50 to 75 nights per year will be available to the community. Proposals will be selected through the NOAO time allocation process. Many potential investigators may be new to interferometry, so CHARA scientists are planning to host a series of community workshops at locations around the US beginning in 2017. In addition, a new CHARA Visitor Support Scientist will work with visiting astronomers to help design, implement, and analyze CHARA observations. Financial support will be offered to those astronomers who opt to travel to Mount Wilson to make observations with the Array. The NSF/MSIP funding will also support the development of an open database of CHARA archival data and the renewal of several subsystems to optimize performance during the open access time.

For further information, please visit the CHARA and NOAO web pages at:

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

NOAO is the US national research & development center for ground-based night time astronomy. In particular, NOAO is enabling the development of the US optical-infrared (O/IR) System, an alliance of public and private observatories allied for excellence in scientific research, education and public outreach.

Our core mission is to provide public access to qualified professional researchers via peer-review to forefront scientific capabilities on telescopes operated by NOAO as well as other telescopes throughout the O/IR System. Today, these telescopes range in aperture size from 2-m to 10-m. NOAO is participating in the development of telescopes with aperture sizes of 20-m and larger as well as a unique 8-m telescope that will make a 10-year movie of the Southern sky.

In support of this mission, NOAO is engaged in programs to develop the next generation of telescopes, instruments, and software tools necessary to enable exploration and investigation through the observable Universe, from planets orbiting other stars to the most distant galaxies in the Universe.

To communicate the excitement of such world-class scientific research and technology development, NOAO has developed a nationally recognized Education and Public Outreach program. The main goals of the NOAO EPO program are to inspire young people to become explorers in science and research-based technology, and to reach out to groups and individuals who have been historically under-represented in the physics and astronomy science enterprise.

The National Optical Astronomy Observatory is proud to be a US National Node in the International Year of Astronomy, 2009.

About Our Observatories:
Kitt Peak National Observatory (KPNO)

Kitt Peak

Kitt Peak National Observatory (KPNO) has its headquarters in Tucson and operates the Mayall 4-meter, the 3.5-meter WIYN , the 2.1-meter and Coudé Feed, and the 0.9-meter telescopes on Kitt Peak Mountain, about 55 miles southwest of the city.

Cerro Tololo Inter-American Observatory (CTIO)

NOAO Cerro Tolo

The Cerro Tololo Inter-American Observatory (CTIO) is located in northern Chile. CTIO operates the 4-meter, 1.5-meter, 0.9-meter, and Curtis Schmidt telescopes at this site.

The NOAO System Science Center (NSSC)

Gemini North
Gemini North

Gemini South telescope
Gemini South

The NOAO System Science Center (NSSC) at NOAO is the gateway for the U.S. astronomical community to the International Gemini Project: twin 8.1 meter telescopes in Hawaii and Chile that provide unprecendented coverage (northern and southern skies) and details of our universe.

NOAO is managed by the Association of Universities for Research in Astronomy under a Cooperative Agreement with the National Science Foundation.