Gemini’s GHOST captures exquisite first light


Gemini South, one of the world’s most prolific and powerful infrared optical telescopes, received a significant capacity boost with the successful installation of a new high-resolution spectrograph called GHOST, constructed by an international consortium. This state-of-the-art scientific instrument will advance our understanding of the earliest stars, the chemical fingerprints of distant planetary systems, and the formation and evolution of galaxies. Gemini South in Chile is one half of the International Gemini Observatory operated by NSF’s NOIRLab.

That Gemini South telescope’s newest scientific instrument — GHOSTthe Gemini High-Resolution Optical SpecTrograph – achieved the first light through exquisite observations of HD222925a remarkably bright, chemically complex star located more than 1400 light-years away toward the southern hemisphere constellation Tucana. This star is an excellent example of the type of objects GHOST will study. Gemini South is one half of International Gemini Observatory.

This is an exciting milestone for astronomers around the world who rely on Gemini South to study the Universe from this extraordinary vantage point in Chile.said Jennifer Lotz, Director of the Gemini Observatory. “Once this next-generation instrument becomes operational, GHOST will be an essential part of astronomers’ toolboxes.”

Spectrographs are among the most important scientific instruments in all of astronomy. Unlike high-resolution cameras that capture amazing detail of distant stars and galaxies, spectrographs precisely analyze the light spectrum emitted by these objects, revealing detailed information about their chemical composition, motion and rotation, as well as ancient counterparts at the edge of the observable universe.

GHOST, which has ten times the spectral resolution of GMOS, Gemini’s other large optical spectrograph, is the most sensitive full-optical-wavelength, high-resolution spectrograph of any spectrograph currently in operation on telescopes of comparable size [1].

GHOST will also provide important follow-up observations of key targets arising from many ongoing and future investigations such as: Vera C. Rubin Observatory‘s Legacy Survey of Space and Time, SkyMapperand GAIA. The tool is freely accessible, meaning that any researcher with a convincing scientific argument can submit proposals to use it for their research. NOIRLab will provide a data reduction pipeline for astronomers using the instrument.

Australian astronomical optics (AAO) at Macquarie University leads the GHOST team, which includes the National Research Council of Canada (NRC) Herzberg Astronomy and Astrophysics Research Center, which was responsible for building the spectrograph, and the Australian National University (ANU), leader in instrument control system and data reduction software.

The design and construction of GHOST began in 2010 and took ten years to complete. The instrument was delivered to Gemini South in early 2020, although COVID-19 restrictions meant installation by the Canadian and Australian teams had to wait until early 2022. With its successful installation and first-light observations, the commissioning team has put GHOST to the test, verifying that its systems are working as designed. Once the commissioning process is complete, it will form part of Gemini South’s diverse suite of advanced optical and infrared instruments and will be offered for use by astronomers.

The installation and commissioning took a long time, but the team worked efficiently and quicklysaid Steve Margheim, GHOST project scientist NSF‘s NOIRLab. “It was a very special day when we saw our first rainbow from the instrument“.

With the successful commissioning of GHOST, NSF congratulates the instrument team for providing the international astronomy community with enhanced ways of studying planets, stars and galaxiessaid Martin Still Gemini Program Officer at the National Science Foundation. “We eagerly await the new discoveries.

GHOST is expected to be made available to the astronomical community in the first half of 2023.


[1] GHOST is an echelle spectrograph and consists of three main components; the Cassegrain unit mounted on the telescope, the spectrograph bench in the pier laboratory for image and wavelength stability, and a fiber optic cable connecting the two.

More information

NSF’s NOIRLab (National Optical-Infrared Astronomy Research Laboratory), the US center for ground-based optical-infrared astronomy, operates the international Gemini Observatory (an institution of NSF, NRC-Canada, ANID-Chile, MCTIC-Brazil, MINCyT–Argentinaand KASI-Republic of Korea), Kitt Peak National Observatory (KPN), Cerro Tololo Inter-American Observatory (CTIO), the science and data center of the community (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the energy authority‘s SLAC National Accelerator Laboratory). It is sponsored by the Association of Universities for Research in Astronomy (AURA) under a collaboration agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research at Iolkam Du’ag (Kitt Peak) in Arizona, at Maunakea in Hawaii, and at Cerro Tololo and Cerro Pachón in Chile. We recognize the very important cultural role and reverence these sites have for the Tohono O’odham Nation, the native Hawaiian community and the local communities in Chile respectively.



Jennifer Lotz
Director, International Gemini Observatory
Email: [email protected]

Amanda Kocz
communications manager
Tel: +1 520 318 8591
Email: [email protected]

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