Starry night at the Atacama Desert coast

From right to left, the Small and the Large Magellanic Clouds, two irregular galaxies neighbourhood of the Milky Way. The observation of these objects was notified for the first time by the Magellan´s expedition at the beginning of the XVI century. By then, they were thought to be –strangely immobile- thin clouds. A “real” cloud leans out of the left horizon. Because of the humidity brought by the cold Pacific Ocean and the thermal contrast with the ground, clouds often cover the coast of the Atacama Desert, providing the humidity that feeds the local flora, consisting in different species of cacti, many of them endemic. The cold temperature of the ocean keeps the so called “inversion layer” very low, while the atmosphere above the clouds is exceptional dry and clear. These are the conditions found at Paranal Observatory, located at an elevation of 2600 metres, only 12 km away from the coast. Mount Paranal is home of the ESO Very Large Telescope (VLT), the most advanced optical ground based telescope in the world.