Atacama Pathfinder Experiment
The Atacama Pathfinder Experiment (APEX ) is a radio telescope with a 12-meter reflector diameter in the Chilean Atacama desert. APEX was jointly organized by the Max Planck Institute for Radio Astronomy (MPIfR ), the European Southern Observatory ( ESO ) and the Onsala Space Observatory ( OSO ) built on the site of the Radiointerferometers Atacama Large Millimeter Array ( ALMA). This is about 5100 meters altitude on the Chajnantor plateau in northern Chile, which is distinguished by its thin and dry air especially for astronomical observations in the submillimeter and millimeter range. APEX operates at 0,2 - 2,0 mm wavelength. The telescope is a slightly modified prototype ALMA antenna, in particular, offer the two Nasmyth cabins additional space for the receiver.
In the summer of 2005, the first scientific observations were carried out with APEX. The scientific focus of the telescope are the research of star formation and of the universe at high redshift.