FMOS: the Fiber Multiple-Object Spectrograph is the next common-use instrument of the Subaru Telescope,
having a capability of 400 targets multiplicity in the near-infrared 0.9-1.8μm wavelength range with a field
coverage of 30' diameter. FMOS consists of three units: 1) the prime focus unit including the corrector lenses,
the Echidna fiber positioner, and the instrument-bay to adjust the instrument focus and shift the axis of the
corrector lens system, 2) the fiber bundle unit equipping two fiber slits on one end and a fiber connector box with
the back-illumination mechanism on the other end on the bundle, 3) the two infrared spectrographs (IRS1 and
IRS2) to obtain 2×200 spectra simultaneously. After all the components were installed in the telescope at the
end of 2007, the total performance was checked through various tests and engineering observations. We report
the results of these tests and demonstrate the performance of FMOS.
The UK FMOS spectrograph forms part of Subaru's FMOS multi-object infrared spectroscopy facility. The spectrograph
was shipped to Hilo in component form in August of 2007. We describe the integration sequence for the spectrograph,
the results of cooldown tests using a new chiller unit fitted to the spectrograph at the telescope, and alignment tests of the
spectrograph, gratings and OH-suppression masks. We present the first-light observations for the spectrograph from May
This paper describes the design and development of an accurate temperature compliant lens mounting technique being
used on the camera of the UK-FMOS near infrared spectrograph for operation at the Subaru Telescope in Hawaii. A
series of fused silica lenses of up to 4.4kg, 255mm in diameter and operating at temperatures as low as 70K are
supported within flexures cut away from stainless steel outer rings. Intermediate low thermal expansion pads are
attached to these flexures and in turn bonded to the glass during the alignment process. This mounting method lends
itself to the domino chips type of assembly process which can be carried out on a rotary table to maintain accurate axial
alignment. A detailed description of the overall design progression including the methods of manufacture, alignment
process, adhesive selection, assembly methods and testing is included.
FMOS is a near-IR OH-suppressed multi-fibre fed spectrograph for the Subaru telescope. The spectrograph will accept 200 optical fibres from the ECHIDNA positioner system at the 30arcmin Prime focus of the telescope. We will describe the recent activities here in the UK in progressing the instrument from its conceptual phase through detailed design and into manufacture. A variety of technical areas will be described including: the opto-mechanical system design and construction, development of the HAWAII-II detector control system, the thermal system design & control and OH suppression techniques.