A NEW “star” has appeared in the southern hemisphere’s sky. It is produced by illuminating a layer of sodium atoms some 90 kilometres up by means of a powerful laser at the Very Large Telescope (VLT) in Cerro Paranal, Chile.
The purpose of the artificial star is to correct the blurring in telescope images caused by turbulence in the Earth’s atmosphere. Turbulence is one of the key factors limiting the resolution and light-collecting ability of Earth-based telescopes. To counter it, astronomers have been developing adaptive optics systems that use lasers to measure the turbulence and then correct for it by…
