The primary aim of PRAXIS is to determine the full astronomical potential of the technique of using fibre Bragg gratings (FBGs) for atmospheric OH suppression in astronomy. To achieve this, we have designed and built a dedicated high-throughput low-noise H-band spectrograph and associated fibre feed and telescope fore-optics unit, in a close collaboration with the Astrophysical Institute Potsdam.

For atmospheric line filtering, the instrument employs the GNOSIS FBG fibre bundle, with a planned upgrade to a new multicore FBG bundle being developed. PRAXIS was commissioned on the AAT, with a plan to later move the instrument to a high altitude telescope in the near future.