AAO delivers Fibre Positioners to Germany

Designed and built by AAO, the AESOP (Australian-European Southern Observatory Positioner) arrived in Potsdam, Germany in late 2021. AESOP is an optical fibre positioner unit for the 4MOST instrument currently under construction for the 4-metre diameter VISTA telescope in Chile, which is operated by the European Southern Observatory (ESO). The 4MOST instrument is currently in the final stages of system integration in Germany and will soon be shipped to the telescope for installation and commissioning.

AAO is responsible for design, assembly, test, delivery, and commissioning of the complete AESOP fibre positioning subsystem. The design for AESOP is an evolution of the AAO’s tilting spine technology, first designed and implemented in the FMOS-Echidna instrument for the Subaru telescope.

AESOP comprises 2448 optical fibres, each mounted in a tilting spine that can be deployed anywhere within its fixed 11.5mm patrol areaThe AESOP instrument can simultaneously position all 2448 fibres to an accuracy of 10 micron (about one fifth the thickness of a human hair) in less than one minute. Once all the fibres are positioned on-target, they will feed the light they collect from each star or galaxy to spectrographs for analysis.

AAO’s optical and fibre engineering capability was gained through decades spent developing advanced instrumentation for astronomy. Fibre positioner technologies are applied in astronomy to enable the control and manipulation of light from astronomical telescopes. The precision mechatronic and opto-mechanics systems upon which these technologies are based have wide applicability in a range of industries (eg. telecommunications, aerospace and medical).

Image left: The AESOP deploying 2448 optical fibres. Credit: AAO/Rebecca Brown. Image right: AESOP assembly process. It took the AAO team several years to design, develop, test, and verify all of the instrument components. Credit: Credit: MQ/AAO