Press Release

Desert Pathfinder at Work

Sub-millimetre APEX telescope inaugurated at Chajnantor

25 September 2005

The Atacama Pathfinder Experiment (APEX) project celebrates the inauguration of its outstanding 12-m telescope, located on the 5100m high Chajnantor plateau in the Atacama Desert (Chile). The APEX telescope, designed to work at sub-millimetre wavelengths, in the 0.2 to 1.5 mm range, passed successfully its Science Verification phase in July, and since then is performing regular science observations. This new front-line facility provides access to the "Cold Universe" with unprecedented sensitivity and image quality.

After months of careful efforts to set up the telescope to work at the best possible technical level, those involved in the project are looking with satisfaction at the fruit of their labour: APEX is not only fully operational, it has already provided important scientific results.

"The superb sensitivity of our detectors together with the excellence of the site allow fantastic observations that would not be possible with any other telescope in the world," said Karl Menten, Director of the group for Millimeter and Sub-Millimeter Astronomy at the Max-Planck-Institute for Radio Astronomy (MPIfR) and Principal Investigator of the APEX project.

The official inauguration of the APEX telescope will start in San Pedro de Atacama on September, 25th.

The Ambassadors in Chile of some of ESO's member states, the Intendente of the Chilean Region II, the Mayor of San Pedro, the Executive Director of the Chilean Science Agency (CONICYT), the Presidents of the Communities of Sequitor and Toconao, as well as representatives of the Ministry of Foreign Affairs and Universities in Chile, will join ESO's Director General, Dr. Catherine Cesarsky, the Chairman of the APEX Board and MPIfR director, Prof. Karl Menten, and the Director of the Onsala Space Observatory, Prof. Roy Booth, in a celebration that will be held in San Pedro de Atacama.

The next day, the delegation will visit the APEX base camp in Sequitor, near San Pedro, from where the telescope is operated, as well as the APEX site on the 5100m high Llano de Chajnantor.

More information

APEX is a collaboration between the Max-Planck-Institut für Radioastronomie (MPIfR), Onsala Space Observatory (OSO), and the European Southern Observatory (ESO). 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 Chile is entrusted to ESO. The First Light of APEX took place in July and is described in eso0522. The APEX web site is at The Press Release of the Max-Planck Society is available in English and German.


Karl Menten
Max-Planck-Institute for Radioastronomy
Bonn, Germany
Tel: +49 228-52 52 97

Lars Aake Nyman
Sequitor Base, Chile
Tel: +56 2 582 02 00

Robert Laing
Garching, Germany
Tel: +49 89 3200 6625

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About the Release

Release No.:eso0531
Legacy ID:PR 25/05
Type:Milky Way : Nebula : Appearance : Dark : Molecular Cloud
Facility:Atacama Pathfinder Experiment


Sub-millimetre image of a stellar cradle
Sub-millimetre image of a stellar cradle