A few extra stars

The biggest obstacle in ground based astronomy is the same thing that causes the stars to twinkle — the atmosphere. This romantic effect is due to the distortion of light as it travels through turbulent gases to reach the Earth's surface. This stunning image, taken from a distance, shows the scientific solution — the 4 Laser Guide Star Facility on ESO's Very Large Telescope (VLT). The lasers form an integral part of the adaptive optics system on the VLT, by beaming artificial stars into the sky. Astronomers can then use these guide laser stars as reference points, allowing them to correct their observations of true celestial bodies.