GeminiFocus April 2018 | Page 15

Gemini staff contributions On the Horizon GHOST’s Cassegrain unit captures first light. The OCTOCAM project receives both a new Principal Investigator and Instrument Scientist as it nears its Preliminary Design Review. And demand is high for the new visiting instrument IGRINS, a broad-band, high- spectral-resolution spectrometer at Gemini South. First Light for GHOST’s Cassegrain Unit In January 2018, the Cassegrain unit for the Gemini High-resolution Optical SpecTrograph (GHOST) arrived safely at Gemini South (Figure 1). It is the first of three primary assemblies to arrive and will be mounted on the telescope’s Instrument Support Structure (ISS); the other two are the spectrograph bench (to be located in the pier lab), and a 30-meter-long fiber cable connecting the two. The Cassegrain unit contains the positioning arm system, the object and sky fiber integral field units (that capture all the light), and their corresponding atmospheric dispersion correctors. Figure 1. Second of two trucks delivering the Cassegrain unit to Cerro Pachón. Credit: David Henderson The Australian Astronomical Observatory designed and built the Casseg- rain unit, with the Australian National University providing the needed software. Members of each organization traveled from Australia to Cer- ro Pachón in Chile to unpack, assemble, and test the unit; they also had critical support from the Gemini South day crew, and from other Gemini GHOST team members. The combined teams prepared and installed the Cassegrain unit on the telescope’s ISS to make the first checks on sky in early February (Figure 2). The team had a successful night of testing, with the instrument perform- ing very well. A few of the evening’s accomplishments included con- firming that GHOSTS’ coordinate systems and field center were aligned within our measurements, and ensuring that the probe map of the po- sitioners was well behaved. The team also mapped the unit’s coordinate systems to the sky, acquired targets repeatedly over the entire seven arc- April 2018 GeminiFocus 13