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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 will combine 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 will be achieved through a 270 m fiber optics (the longest ever made for astronomy) feed from the Gemini North telescope to ESPaDOnS. The on-sky size of the fiber will be 1.2 arcsec.
Planned for 2014 (there is a possibility of a call for System Verification programs during 2014B), GRACES will perform a maximum resolution power of R ~ 50,000 between 400 and 1,000 nm, with expected throughput redward of 600 nm exceeding those of currently available high-resolution spectrographs in 8-10 m class telescopes. The Gemini Multi-Object Spectrograph (GMOS-N) will hold the fiber injector on the Gemini side, and will be used for acquiring targets. The GMOS-N On-Instrument Wave Front Sensor (OIWFS) will be used for guiding, but the Peripheral WFSs could also be chosen under certain circumstances. On the other end of the fiber, GRACES will use its own slicer bench inside 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.
GRACES is currently designed as an experiment and a future decision about providing GRACES for science observations is dependent upon measured on-sky performance and reaching a long term agreement to share this facility between CFHT and Gemini.
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.
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 to be obtained in 2014B.
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).