The Atacama Pathfinder Experiment (APEX) is a radio telescope located at 5,100 meters above sea level, at Llano de Chajnantor Observatory in the Atacama desert, in northern Chile, 50 kilometers to the north of San Pedro de Atacama.

The APEX telescope is a modified ALMA (Atacama Large Millimeter Array) prototype antenna and is located at the future site of the ALMA observatory. It is designed to work at sub-millimetre wavelengths, in the 0.2 to 1.5 mm range. The main dish has a diameter of 12 meters and consists of 264 aluminium panels with an average surface accuracy of 17 micrometres (r.m.s.).

APEX is a collaboration between the Max-Planck-Institute for Radio Astronomy (MPIfR) at 50%, Onsala Space Observatory (OSO) at 23%, and the European Organisation for Astronomical Research in the Southern Hemisphere (ESO) at 27%. The telescope was designed and constructed by VERTEX Antennentechnik GmbH (Germany), under contract by MPIfR, and is based on a prototype antenna constructed for the ALMA project. Operation of APEX in Chajnantor is entrusted to ESO.

APEX was officially inaugurated on September 25th, 2005.

External link

• Official site

Radio telescopes | Astronomical observatories in Chile

Atacama Pathfinder Experiment | Atacama Pathfinder Experiment | Atacama Pathfinder Experiment