Four Laser Guide Star Facility at the VLT. Illustration of artificial laser stars (orange beams) rising from a unit of the European Southern Observatory's VLT (Very Large Telescope), Cerro Paranal, Chile. By focusing on the artificial guide stars in the form of the laser beams, VLT telescopes are calibrated to remove the effects of the atmosphere on observations, a process known as adaptive optics. This is Unit Telescope 4, with the lasers produced by the VLT's 4 Laser Guide Star Facility, which was switched on in April 2016. These are the most powerful laser guide stars ever used for astronomy and mark the first use of multiple laser guide stars at ESO. The labelled components include Raman lasers, reference lasers, pump lasers, and the beam control and frequency doubler mechanisms. |