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Gemini Remote Access to CFHT ESPaDOnS Spectrograph (GRACES) is the result of a cooperation between the Canada-France-Hawaii Telescope (CFHT), Gemini, and NRC-Herzberg (Canada). It combines the large collecting area of the Gemini North telescope with the high resolving power and high efficiency of the ESPaDOnS spectrograph at CFHT, to deliver high resolution spectroscopy across the optical region. This is achieved through a 270 m fiber optics feed from the Gemini North telescope to ESPaDOnS. The on-sky size of the fiber is 1.2 arcsec.
GRACES performs a maximum resolution power of R ~ 67,500 between 400 and 1,000 nm, with throughput redward of 600 nm comparing those of currently available high-resolution spectrographs in 8-10 m class telescopes. The Gemini Multi-Object Spectrograph (GMOS-N) holds the fiber injector on the Gemini side, and is used for acquiring targets. The GMOS-N On-Instrument Wave Front Sensor (OIWFS) is used for guiding, but the Peripheral WFSs could also be chosen under certain circumstances. On the other end of the fiber, GRACES uses its own slicer bench inside of ESPaDOnS before the light is sent inside the CFHT's echelle spectrograph. For more information about ESPaDOnS, please visit this page at CFHT.
The Instrument Scientist for GRACES is André-Nicolas Chené. Gemini staff who also supports GRACES include Vinicius Placco and Percy Gomez. The CFHT contact for GRACES is Lison Malo.
GRACES will be installed and improved over the 2015A semester, and will be offered as Visiting instrument in 2015B.
12 Jan 2015: A MoU about CFHT/Gemini GRACES Collaboration Agreement is signed.
Nov 2014: GRACES phase II is approuved and the instrument is planned to be offered as a visiting instrument in 2015B.
21 Jul 2014: GRACES phase I results are presented at the SPIE meeting in Montréal.
16 May 2014: GRACES phase I (experimental phase) commissioning is now completed. The fibers were installed on 24 Apr (see this Youtube video on the Gemini Observatory Channel). The first tests on-sky started on 30 Apr when light was successfully sent through the fibers from the Gemini mirror to a camera installed into the CFHT dome. GRACES fiber was connected to the ESPaDOnS spectrograph on 5 May, and the first light was achived on 6 May!
3 mar 2014: Acceptance tests of all the optical and mechanical parts are currently running (Mar 2014). If GRACES performances in the lab are satisfactory, its commissioning will be performed during (Hawaiian) spring. GRACES availability will be decided once the commissioning is completed.
10 Feb 2014: FiberTech Optica achieved to make two 270m fibers that meet the requirement of an average 20% focal ration degradation.
GRACES science highlights
First science data are expected for 2015B.
How to use these pages
The GRACES pages are organized as follows.
- Status and Availability: Time windows when GRACES will be available in the semester.
- Spectroscopy: Characteristics of GRACES modes, camera configurations, filters, and guidelines on how best to use the instrument.
- Polarimetry: This mode is not available at the moment, but may become possible in the future.
- Exposure time estimation and Overheads: Integration time estimation and details of observing overheads.
- Throughput and sensitivity: Throughput and sensitivity tables.
- Guiding Options: Guiding considerations, and wavefront sensors available for use with GRACES.
- Calibration: Info on GCAL flats and arcs, standard stars, and baseline calibrations.
- Observation Preparation: How to configure GRACES in the Observing Tool.
- Data Format and Reduction: Examples of GRACES data and links to data reduction resources.
- Basic design: Overall design of GRACES, including the slicer bench sitting inside the ESPaDOnS spectrograph, the fiber injectors inside GMOS and the path of the optical fibers.
- Documents: GRACES optical layout; design documents and references.
CFHT and Gemini domes next to each other on the Mauna Kea summit (credits Joy Pollard, Gemini/Aura).