Astronomers and amateur skywatchers (pictures above) were treated to a total solar eclipse in part of Chile's northern desert, an area famed for its clear skies and host to some of the world's largest telescopes. More than 200,000 people flocked to the coastal resort of La Serena and the nearby Elqui Valley to witness the moon's shadow cover the sun for 2 minutes and 36 seconds at 4.39pm local time on Tuesday. Such eclipses happen once every few months, but this year's took place in a region that attracts tens of thousands of amateur astronomers every year. About half of the world's observation capacity is now installed in Chile and with new mega telescopes under construction, that number is set to rise to 70 per cent by 2020. The country hosts seven of the world's 18 largest optic telescopes, as well as the world's most powerful and modern radio-telescope. High altitude, low humidity, cloudless skies and a lack of light pollution make northern Chile's skies the world's clearest. While the eclipse was not total further south in the capital Santiago, thousands of Chileans still watched from the city's most emblematic spots, including the Costanera tower, South America's tallest building. The special glasses required to see the eclipse ran out in many stores earlier in the week. By Tuesday, those who could not find them were taking the risk and making their own.