The Precision Integrated-Optics Near-infrared Imaging ExpeRiment (PIONIER) is a visiting instrument at the ESO's Paranal Observatory,[1] part of the VLTI astronomical observatory. It combines the light from four telescopes simultaneously and provide 0.002 arc seconds of angular resolution, the equivalent angular resolution of a 100 m telescope.
PIONIER has been built at LAOG and has been installed at VLTI in November 2010.