GHOST Commissioning

GHOST, the Gemini High-resolution Optical SpecTrograph, is the next Gemini facility instrument and will provide world-class, high-resolution spectroscopic capabilities to the Gemini community. It is an instrument for Gemini South in Chile. Australian Astronomical Optics (AAO) at Macquarie University leads the GHOST team, which includes the National Research Council Herzberg (NRC-H), for the construction of the spectrograph and the Australian National University (ANU) leads on the instrument control system and data reduction software.

Major components of GHOST were delivered to the AURA Recinto in Chile just after the pandemic started and remained there for 8 months before they were delivered to Gemini South in February 2021.

Now, with travel restrictions lessened, teams from NRC Canada, AAO Australia, and Gemini North are working with the Gemini South GHOST project team and the rest of the Cerro Pachón day crew to assemble the GHOST spectrograph.

The teams are into week four of this effort, and they are on schedule to commission GHOST in late June. Twilight tests are due to take place in late May. The following milestones have already been met:

• 75% of the 9-feet-tall outer enclosure assembly completed
• Optical bench support structure assembled and 1000-lb bench installed
• All the optics inspected, finding no shipping damage or coating degradation from long storage
• All optics mounted on the optical bench, and white pupil relay aligned
• Both detectors under vacuum
• All electronics unpacked, inspected and tested; assembly is ~ 50% complete

GHOST will enable astronomers to investigate a broad range of science goals, from the composition of the first stars to the characterization of exoplanetary systems. GHOST will also provide crucial follow-up of interesting targets emerging from many ongoing and future surveys, such as Vera C. Rubin Observatory’s Legacy Survey of Space and Time, SkyMapper and GAIA.