GeminiFocus July 2013 | Page 22

Currently, GRACES is scheduled for on-sky commissioning in October or December of this year. Integration and Testing of the opto-mechanical systems at HIA is planned for July to September, after which it will be shipped to Mauna Kea for installation, daytime testing, and then commissioning. After that, GRACES will become available to Gemini’s users in block observing mode (not queue mode). Figure 5: Model rendering of the injector unit. The optics are housed in a GMOS-N filter cassette (large grey unit). The blue light rays in the center of the unit are the two input beams from Gemini (star and sky), which reflect off a mirror to the upper right where they are fed into two 270-meter-long fibers. Figure 6: Model rendering of the slicer bench. The ESPaDOnS optical beam passes though the large rectangular opening in the bottom half of the structure. The top structure houses the optical fiber inputs, the optics, adjustment stages, and the image slicer. The optical-fiber-cable attaches through the top of the assembly where it passes through the optics and slicer down to the fold mirror (grey and brown piece projecting down into the bottom half) to be inserted into ESPaDOnS. 22 hardware parts are being fabricated in the machine shop at the Dominion Astrophysical Observatory (formerly the Herzberg Institute for Astrophysics). Figures 5 and 6 show computer-aided design model pictures of the injector unit (Gemini end) and the slicer unit (ESPaDOnS end). The injector unit uses a Gemini North MultiObject Spectrograph (GMOSN) filter cassette, which allows GMOS-N to act as an acquisition camera for GRACES. Permanently installed in ESPaDOnS, the slicer includes a deployable fold mirror that allows ESPaDOnS to be used with the CFHT or GRACES by simply moving the fold mirror in and out of the optical path of ESPaDOnS. Critically, this can be done without affecting the alignment or performance of either instrument. Finally, we’ve &V6V