A laser star shines bright

An artificial star now shines above the European Southern Observatory in Paranal, home of the Very Large Telescope, allowing astronomers to better allow for the optical effects of the atmosphere


An artificial star now shines above the European Southern Observatory (ESO) in Paranal, home of the Very Large Telescope (VLT), allowing astronomers to better allow for the optical effects of the atmosphere.



The laser-produced image helps the adaptive optics instruments on the VLT to obtain images free from the blurring effect of the atmosphere, regardless of the brightness and the location on the sky of the observed target.



Adaptive optics requires a nearby reference star that has to be relatively bright, limiting the area of the sky that can be surveyed. To surmount this limitation, Paranal astronomers now a powerful laser that creates an artificial star, where and when they need it.



Two of the Adaptive Optics (AO) science instruments at the Paranal observatory, NACO and SINFONI, have been upgraded to work with the recently installed Laser Guide Star (LGS) and have delivered their first scientific results. This achievement opens astronomers’ access to a wealth of new targets to be studied under the sharp eyes of AO.



The Laser Guide Star System installed at Paranal uses the PARSEC dye laser developed by the Max Planck Institute for Extraterrestrial Physics (MPE) and the Max Planck Institute for Astronomy (MPIA), while the launch telescope and the laser laboratory was developed by ESO.



‘To test the laser guide star adaptive optics system to its limits, and even beyond, we observed a number of galaxies, ranging from a close neighbour to one that is seen when the universe was very young,’ said Markus Kasper, the NACO Instrument Scientist at ESO.



The first objects that were observed are interacting galaxies. The images obtained reveal a high level of detail, and have a resolution comparable to that of the Hubble Space Telescope. In one case, it was possible to derive for the first time the motion of the stars in two merging galaxies, showing that there are two counter-rotating discs of stars.