AAO to build fiber positioner for ESO's VLT AT Paranal

17 Jun 2002

The European Space Agency has selected the Anglo-Australian Observatory to build a fiber positioner for ESO's Very Large Telescope (VLT) which will be located at the Paranal Observatory in Chile.

The positioner for the VLT is known as the OzPoz. It is a tumbling system analog to the 2DF (two-degree field) positioner which is now fully operational at the Anglo-Australian Telescope. The fibers are put in position while the system is observing on the sky, which results in minimal loss for the observation setup.

In addition to the 3.9 meter Anglo-Australian Telescope, the AAO has also built the optical fiber instrument for the 1.2 meter Schmidt Telescope.

The OzPoz positioner will be the heart of the FLAMES (Fibre Large Area Multi-Element Spectrograph) which will be mounted on the second unit telescope of the four-telescope VLT facility. Each of those telescopes will have a diameter of 8.2 meters.

OzPoz will be able to feed the UVES (UV-Visual Echelle Spectrograph) with eight individual fibers, providing a spectral resolution of 40,000 on eight different stars. OzPoz will be able to feed the GIRAFFE optical spectrograph, which has a spectral resolution of about 15,000, with single fibers, small packs of fibers, or a single large pack. OzPoz will also be able to feed the AUSTRALIS near-IR spectrograph which has a spectral resolution of about 12,000 in the 1.0-1.8 micron range.

OzPoz will set up to 560 optical fibers, which will be developed in collaboration with the Observatoire de Meudon in France, by a robotic arm to match the positions of galaxies and quasars in the telescope's focal plane. A positional accuracy of about 50 microns or 0.08 arcsec on the sky is expected. The fibers will siphon the light from those astronomical objects and guide it to the efficient, custom-designed spectrographs, where the light will be dispersed into its characteristic colors and analyzed to determine the object type, distance, chemical composition, and other characteristics.

Within a single night OzPoz will be able to obtain optical and infrared spectra for over 3,000 objects, including distant galaxies.

By the time the OzPoz positioner is ready, the Sydney Olympics will have passed. The effort will take about three years and will be mounted on the VLT in 2001.