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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.
Mar 5, 2014: GRACES is now offered for the 2015B call for proposals.
NOTE: It was decided to not send a call for System Verification (SV) programs. Future insterested PIs can rather prepare a real proposal for 2015B.
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).