Astronomers at the European Southern Observatory’s Very Large Telescope (VLT) in Chile have been using a powerful new instrument since early in 2003. The VLT comprises four optical telescopes, each having an aperture over 8 metres diameter. This new spectroscopic instrument called "FLAMES" is fed through as many as 150 optical fibres at a time by OzPoz, designed and built in Sydney by the Anglo-Australian Observatory (AAO). OzPoz positions the input ends of the fibres to align them accurately (within 0.05 mm) with the images formed by one of the 8 metre telescopes of faint celestial targets scattered over a field as large as the full moon.

The main structure for OzPoz was fabricated and assembled by Chess Engineering to exacting tolerances, with allowances for shrinkage of the complex components that were to be both welded and stress relieved.

The steel plates of the main support were laser cut to maintain accuracy while the focal plates with their spherical concave form were machined on a CNC lathe and hand-honed to the specified level of finish.

Chess has established a reputation for accurate engineering of structures for astronomical instruments. A previous contract was for a new top end for the AAO’s 4 metre diameter telescope at Coonabarraban. This top end supports a multi-fibre feed, known as 2dF, with which the AAO has completed two world-leading spectroscopic surveys of galaxies and quasars.

Images published courtesy of the Anglo-Australian observatory

http://www.aao.gov.au/

http://www.eso.org/instruments/flames/OzPoz.html/