Unit-ed telescopes

Unit Telescope 4 (Yepun) of ESO's Very Large Telescope (VLT) takes centre stage in this image from the Paranal Observatory, which is located on Cerro Paranal, a 2600-metre high mountain in the Chilean Atacama Desert. The three other Unit Telescopes are visible to the right of Yepun, from front to back: UT3 (Melipal), UT2 (Kueyen) and UT1 (Antu). The laser light from Yepun is creating an artificial guide star that the Adaptive Optics technology uses to correct the blurring effects of the Earth's atmosphere to create sharper images. Each UT is a highly advanced telescope in its own right, with its own instruments specialised to collect data for certain fields of study. When used in combination they form the VLT, the world's most advanced optical instrument.