La Silla Observatory La Silla Observatory is an astronomical observatory in Chile with eighteen telescopes . Five of these telescopes were built by the European Southern Observatory ( ESO ) organisation , and several of the others are partly maintained by ESO. The observatory is one of the largest in the Southern Hemisphere . La Silla is a 2400 m high mountain , bordering the southern extremity of the Atacama desert in Chile . It is located about 160 km north of La Serena . Its geographical coordinates are : latitude 29º 15.3 ' south and longitude 70º 44.3 ' west . Originally known as Cinchado , the mountain was renamed La Silla ( the saddle ) after its shape . It rises quite isolated and remote from any artificial light and dust sources ( astronomy 's worst enemies ) . La Silla was the observatory in Chile used by ESO. Its history is full of optimism and disappointments , ups and downs , since its beginnings in the 1950 's until the middle of the 1970 's when the observatory became a reality . Telescopes at La Silla Observatory NTT ( 3.5 m ) Built and operated by ESO 3.6 m Built and operated by ESO 2.2 m Built and operated by ESO ESO 1.5 m Built by ESO , now decommissioned ESO 1 m Built by ESO , now decommissioned ESO 0.5 m Built by ESO , now decommissioned DENIS 1 m   MARLY 1 m ( EROS project )   Geneva 1.2 m   Danish 1.5 m   Danish 50 cm   Dutch 90 cm   SEST 15 m Built by ESO , now decommissioned Marseille 40 cm   Bochum 61 cm   CAT 1.4 m Built by ESO , now decommissioned IRIS   Schmidt 1 mm Built by ESO , now decommissioned GPO ( replaced by Marly 1 m )   External links Website for the ESO telescopes at La Silla Coordinates : 29°15′S 70°44′W Categories : Astronomical observatories in Chile In other languages : Deutsch | Español | Français | Italiano 29 15 S 70 44 W 