This image may not be used by or to promote the arms, nuclear power or tobacco industries or any religious organisation, or in any discriminatory way,

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This image may not be used by or to promote the arms, nuclear power or tobacco industries or any religious organisation, or in any discriminatory way, or to imply the endorsement by ESO of any product, service or activity VLT Interferometer PRIMA instrument being tested in a laboratory. The PRIMA (Phase Referenced Imaging and Microarcsecond Astrometry) instrument was deployed in 2008 on the VLTI (Very Large Telescope Interferometer). These are the two combined beams of PRIMA's fringe sensor unit (FSU) B, joining the FSU's beam combiner (top) to the fibre injection optics (bottom). PRIMA was installed to improve the sensitivity of the VLTI, which combines images from separate telescopes at the VLT (at the Paranal Observatory, Chile) increase the effective mirror size. Photographed during tests at ESO headquarters in Garching, :

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Photo credit: © EUROPEAN SOUTHERN OBSERVATORY/H. HEYER/SCIENCE PHOTO LIBRARY / Alamy / Afripics
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