Atacama Pathfinder Experiment (APEX)
APEX, the Atacama Pathfinder Experiment, is a collaboration between Max Planck Institut für Radioastronomie (MPIfR) at 55%, Onsala Space Observatory (OSO) at 13%, and the European Southern Observatory (ESO) at 32% to construct and operate a modified ALMA prototype antenna as a single dish on the high altitude site of Llano Chajnantor. The telescope was manufactured by VERTEX Antennentechnik in Duisburg, Germany.
Observing with APEX allows us to study cold dust and gas in our own Milky Way and in distant galaxies. Tracing the thermal continuum emission and analyzing high frequency spectral lines improve our understanding of the structure and chemistry of planetary atmospheres, dying stars, regions of star formation as well as distant starburst galaxies. We can address issues from the vast scales of the structure of the Universe down to the physics and chemistry of comets. — APEX official website