To see distant stars and planets, astronomers must first calibrate their equipment to compensate for Earth’s blurry atmosphere — and that’s a whole lot easier said than done. In fact, to pull it off, they have to actually create artificial stars, dubbed ‘guide stars’, using really, really big lasers.

Now, researchers from the European Southern Observatory’s (ESO) Paranal Observatory in Chile have created the most powerful one to date — a system they call the Four Laser Guide Star Facility (4LGSF).

The new system, which has been tested since last September, works by shooting four 29.9-centimetre (11.8-inch), 22-watt beams into the atmosphere to basically mark the sky.