Artificial stars over Paranal

At the isolated Very Large Telescope (VLT) at ESO's Paranal Observatory, the arid desert offers near perfect conditions for observations. However, the atmosphere still distorts light from distant objects, and astronomers often use 'reference stars' with known properties to compare and correct images. But if a suitable star isn't available, the VLT now has a perfect solution - simulate one! The new system of four lasers allows astronomers to create artificial reference stars to improve their results.