LArge APEX BOlometer CAmera

Located at 5100 metres altitude, high on the Chajnantor Plateau in Chile’s Atacama region is the Atacama Pathfinder Experiment Telescope or APEX. This pioneering 12-metre telescope, operating at millimetre and submillimetre wavelengths, allows astronomers to study the cold Universe: gas, dust and celestial objects that are only a few degrees above absolute zero (-273.15° C).

To measure this cold Universe, we need a thermometer of some kind. At the heart of APEX is LABOCA, or the LArge APEX BOlometer CAmera, the largest bolometer in the world. In essence it is a thermometer which measures the incoming radiation by registering the resulting rise in temperature.  What makes LABOCA special is that it is composed of 295 bolometers arranged in an hexagonal unit.

To understand how LABOCA works try to imagine an extremely thin sheet of foil that absorbs the incoming light. Any change in the intensity of the incoming radiation results in a slight change in temperature of the foil, which can then be registered by sensitive electronic thermometers,and  the signals are then amplified and recorded for later analysis.

To register these tiny temperature fluctuations, the bolometers must be cooled to less than 0.3 degrees above absolute zero, and so LABOCA detectors are kept in a high-vacuum cryostat system that uses liquid nitrogen and liquid helium to cool it down.

Closer to home, LABOCA is studying Kuiper Belt Objects in the Solar System, looking for clues to as to how our own planetary system, and planets in general, formed. It is also particularly useful in the study of star formation in the Milky Way (eso1431). LABOCA’s ability to map large areas of sky with high sensitivity is exploited by surveys of the distribution of the cold dust in our galaxy. Through subsequent analysis of the gas properties of a large number of clouds and clusters it is possible to work out where new stars are being born in the Milky Way and develop a detailed understanding of their evolution.

All these characteristics have made LABOCA and APEX  the perfect partners to work side by side (also literally) with ALMA to explore the cold Universe.

Science highlights with LABOCA

  • APEX reveals hidden star formation in protocluster (eso1431)
  • The Wild Early Lives of Today's Most Massive Galaxies (eso1206)
  • List of the scientific papers produced by LABOCA , via the ESO library TelBib database.


The authoritative technical specifications as offered for astronomical observations are available from the Science Operation page.

Name: LArge APEX BOlometer CAmera
Site: Chajnantor Plateau
Telescope: APEX
Focus: Cassegrain
Type: Submillimetre
Wavelength coverage: 870 μm
Angular resolution: 18.6 arcseconds
First light date: August 2007 (eso0735)
Images taken with the instrument: Link
Images of the instrument: Link

Videos of the instrument:


Press Releases with the instrument: Link
Science goals: Star formation, molecular clouds, distant Universe


Max Planck Institute for Radioastronomy (MPIfR) in Bonn