La Silla Observatory at night, Chile. In the night sky, the Milky Way galaxy peeks above the horizon. On the horizon at right stands the domed enclosure of the ESO 3.6-metre telescope and its adjacent smaller sibling, the now-decommissioned Coude Auxiliary Telescope. To the left is the receiver dish for the Swedish?揈SO Submillimetre Telescope, also now decommissioned. Visible in the far distance are city lights which, although faint in absolute terms, can become noticeable over long exposures such as this one. The soft glow of light just to the left of centre, which gently curves through the sky, is called zodiacal light. It is sunlight scattered by dust particles in the plane of the Solar System.