The First Light APEX Submillimeter Heterodyne (FLASH) instrument was installed at the Nasmyth–A Atacama Pathfinder Experiment (APEX) telescope on the Chajnantor plateau in Chile’s Atacama region in 2004. The development of FLASH was a collaboration between SRON and the University of Cologne.

FLASH was a dual-frequency receiver that operated simultaneously on orthogonal polarisations in the 0.65 mm (460 GHz) and 0.87 mm (345 GHz) atmospheric windows. In its first incarnation FLASH was equipped with a 0.37 mm (810 GHz) and a 0.65 mm (460 GHz) channel. It had a wide tuning range between 0.34 and 0.38 mm (780 and 880 GHz) and between 0.60 and 0.71 mm (420–500 GHz) and intermediate frequency bandwidths of 2 and 4 GHz, respectively. It was the high-frequency heterodyne workhorse during the commissioning of the APEX in its first years of operation. After the successful installation of the CHAMP+ array, also covering the 0.37 mm (810 GHz) atmospheric window, the high-frequency channel was replaced with a state-of-the-art sideband separating 0.87 mm (345 GHz) detector.

FLASH instrument was decommissioned in 2012 and replaced with FLASH+.


This table lists the global capabilities of the instrument.

Location: Decommissioned
Telescope: APEX
Focus: Nasmyth–A
Type: Receiver
Wavelength coverage:

0.65–0.87 mm

Spatial resolution:

17.7′′ [0.87 mm]
13.2′′ [0.65 mm]
7.6′′ [0.37 mm]

Spectral resolution:

38 kHz [0.87 mm channel]
76 kHz [0.65 mm channel]

First light date: June 2004
Science goals:
  • Astronomical line surveying
Images taken with the instrument: N/A
Images of the instrument: N/A
Press Releases with the instrument: N/A
Data papers:

(Includes ESO and non-ESO papers)

ESO data citation policy


  • ESO
  • MPIfR, Germany
  • SRON, the Netherlands
  • University of Cologne, Germany