APEX - Atacama Pathfinder Experiment

APEX, the Atacama Pathfinder Experiment, is a 12 m diameter submillimetre telescope at 5100 m altitude in th​e Atacama Desert in northern Chile.

APEX was inaugurated in September 2005, and provides almost unique opportunities for astronomers to use submillimetre observations to study the first galaxies and how stars and planets are formed.

The APEX project (Güsten et al. 2006, Astronomy & Astrophysics, vol. 454, L13) is a collaboration between Onsala Space Observatory, Max Planck Institut für Radioastronomie (Germany), and the European Southern Observatory to construct and operate a modified ALMA prototype antenna as a single dish on the high altitude site of Llano Chajnantor. The telescope was supplied by VERTEX Antennentechnik in Germany.

Onsala Space Observatory, through the Group for Advanced Receiver Development (GARD), provides heterodyne receivers for APEX.

The Swedish Heterodyne Facility Instrument, SHFI, covered several frequency bands up to 1.3 THz. SHFI was decommissioned in 2017. 

The receiver SEPIA (Swedish ESO PI receiver for Apex) was installed in 2015. When complete, it will include channels for ALMA Band 5 (159-211 GHz), ALMA Band 7 (272-376 GHz), and ALMA Band 9 (600-722 GHz).


​Scientific publications containing APEX data 

In scientific publications containing APEX data please:

  • Acknowledge the project with the following footnote: "Based on observations with the Atacama Pathfinder EXperiment (APEX) telescope. APEX is a collaboration between the Max Planck Institute for Radio Astronomy, the European Southern Observatory, and the Onsala Space Observatory."
  • Give the project ID for the observations.
  • Give proper references to papers about the telescope and receiver(s).
Use the following references to instrumentation papers:
See the APEX web site for references to papers about other instruments. 

Contact person

Per Bergman
Email: per.bergman@chalmers.se, Phone: +46 31 772 5569


APEX web site
> http://www.apex-telescope.org/

Proposals for observations on Swedish time on APEX
Calls for proposals are normally issued twice per year, with deadlines in April/May and October (see link below for detailed information). Swedish time on APEX is open for scientists from all countries.
> http://www.chalmers.se/en/centres/oso/radio-astronomy/proposals/Pages/default.aspx

Observed projects
Observed projects on Swedish APEX time
> http://www.chalmers.se/en/centres/oso/radio-astronomy/apex/Pages/Observed-projects.aspx

ESO Science Archive Facility
> http://archive.eso.org/cms.html

ESO Science Archive APEX Query Form
> http://archive.eso.org/wdb/wdb/eso/apex/form​​

Published: Tue 03 Sep 2013. Modified: Mon 23 Apr 2018