FMOS (Fibre Multi Object Spectrograph)

Components of the large collimator mirror - FMOS

FMOS (Fibre Multi Object Spectrograph) is a spectrograph used in astronomy to measure the infra-red spectra from 400 celestial objects simultaneously and takes advantage of the large 30' field of view of the 8.2m Subaru telescope in Hawaii. RAL Space played a leading role in its design and development within the collaboration between the UK, JAXA (the Japanese Space Agency) and AAO (the Anglo-Australian Observatory).

FMOS camera being tested

The optical design shows the key components of the large collimator mirror, diffraction grating gratings and the cryogenic camera, which was built within the Imaging Systems division. The camera contains some of the largest fused silica lenses used temperatures as low as 70K where the mount design was critical in protecting the lenses and maintaining their alignment. Figure 2 shows the camera being tested with our 4d-Phasecam vibration insensitive interferometer.