Complex sentence: The VISTA (Visible and Infrared Survey Telescope for Astronomy) is a 4-metre class wide-field telescope at the Paranal Observatory in Chile that has been operated by the European Southern Observatory since December 2009.
Split into simpler sentences: The VISTA (Visible and Infrared Survey Telescope for Astronomy) is a 4-metre class wide-field telescope at the Paranal Observatory in Chile. It is operated by the European Southern Observatory since December 2009.