24 robot arms of the K-Band Multi-Object Spectrograph

What is this? This impressive image is an intricate circle of 24 robotic arms that forms part of the European Space Agency’s new K-Band Multi-Object Spectrograph, or KMOS for short.   Image © ESO

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The K-band Multi Object Spectrograph (KMOS) at southern Chile observatory, is a second-generation instrument designed for operation on the VLT. The key feature of KMOS is its ability to perform Integral Field Spectroscopy in the near-infrared bands for 24 targets simultaneously.

The instrument design employs 24 configurable arms that position pickoff mirrors at user- specified locations in the Nasmyth focal plane. The sub-fields thus selected are then fed to 24 image slicer integral-field units (IFUs) that partition each sub-field into 14 identical slices, with 14 spatial pixels along each slice. Light from the IFUs is then dispersed by three cryogenic grating spectrometers which generate 14×14 spectra with ~1000 Nyquist-sampled spectral resolution elements for each of the 24 independent sub-fields. All 24 subfields have to be used with the same grating at a time.

source ESO