Set lasers to star mode. The European Southern Observatory’s Paranal Observatory in Chile now has four powerful laser beams with which to create artificial stars in the night sky.


Engineers at the observatory have been testing the system since last September. The first successful use of the lasers yesterday marked the brith of the most powerful laser guide stars ever used for astronomy.

The cutting-edge laser system, called 4 Laser Guide Star Facility (4LGSF), shoots four impressive 22-watt beams at the sodium wavelength of 589 nanometers. Each beam is 11.8 inches wide. Thankfully they won’t be used for annihilating planets, though, as ESO explains:


The Four Laser Guide Star Facility (4LGSF) shines four 22-watt laser beams into the sky to create artificial guide stars by making sodium atoms in the upper atmosphere glow so that they look just like real stars. The artificial stars allow the adaptive optics systems to compensate for the blurring caused by the Earth’s atmosphere and so that the telescope can create sharp images. Using more than one laser allows the turbulence in the atmosphere to be mapped in far greater detail to significantly improve the image quality over a larger field of view.

Schematic view of the Four Laser Guide Star Facility installed on the Unit Telescope 4 of ESO’s Very Large Telescope. Image: ESO/L. Calçada