The Very Large Telescope's 4 Laser Guide Star Facility

ESO's Very Large Telescope (VLT) consists of an array of four telescopes, each with a main mirror of 8.2 metres diameter, and several smaller telescopes dedicated to interferometry. The large telescopes can observe together or individually. The VLT's laser guide star can clearly be seen in this image; the telescope uses this laser to adapt its optics to account for turbulence in the atmosphere of the Earth, thus producing a clearer image. Here is a very rare moment when the night sky is fully covered by a thin layer of Cirrostratus clouds, and a lunar halo is seen over Cerro Paranal.