Atacama Desert

The Atacama Desert is a 40,000 square mile plateau in Chile. Its altitude varies, but 7,000 feet is common and its highest peaks exceed 22,000 feet. The plateau is clear and dry with an average of 30 cloudy days per year, and an average annual rainfall of about a millimeter. This leaves many cloudless days/nights suitable for observation, and also means less absorption from water lines, i.e., more substantial atmospheric windows for far infrared and microwave. Observatories and telescopes include:

• Atacama Cosmology Telescope (ACT)
• Atacama Large Millimeter Array (ALMA)
• Atacama Pathfinder Experiment (APEX)
• Atacama Submillimeter Telescope Experiment (ASTE)
• BlackGEM
• European Southern Observatory Very Large Telescope (ESO VLT)
• Huan Tran Telescope (HTT)
• Llano de Chajnantor Observatory
• Las Campanas Observatory (LCO)
• Magellan Telescopes
• NANTEN2
• Paranal Observatory
• VLT Survey Telescope (VST)

La Silla Observatory (LSO) is adjacent to the desert, and includes the New Technology Telescope (NTT) and ESO 3.6m Telescope.

Plans and under construction:

• AtLAST (plan)
• CCAT (past plan)
• Cherenkov Telescope Array (CTA)
• European Extremely Large Telescope (E-ELT)
• Fred Young Submillimeter Telescope (FYST) (CCAT-P)
• Giant Magellan Telescope (GMT)
• Leighton Chajnantor Telescope (LCT) (relocation of Caltech Submillimeter Observatory, CSO)
• Large Submillimeter Telescope (LST) (plan)
• Simons Observatory (SO)
• Simons Array
• University of Tokyo Atacama Observatory (TAO)