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 2012. FLASH+ is a principal investigator (PI) heterodyne instrument of the Max Planck Institute for Radio Astronomy (MPIfR) that is permanently installed at the APEX telescope.

FLASH+ is a dual-channel receiver that allows parallel observation in the 0.65 mm (460 GHz) and 0.87 mm (345 GHz) atmospheric windows, with a tuning range between 0.58 and 0.80 mm (374 and 516 GHz) and between 0.80 and 1.12 mm (268–374 GHz). In total, FLASH+ has a 16 GHz, simultaneously processing bandwidth. FLASH+ is equipped with state-of-the-art sideband separating mixers (SIS) provided by IRAM (0.87 mm) and NAOJ (0.65 mm) and its operation is fully automated allowing flexible remote observations from the APEX base in San Pedro de Atacama.

FLASH+ is a uniquely efficient line mapping spectrometer that has already serviced a wide range of scientific projects, including spectral scans towards bright galactic star-forming cores and towards active galactic nuclei, as well as broad-line studies of the Milky Way centre.


This table lists the global capabilities of the instrument.

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

0.58–1.12 mm

Spatial resolution:

17.7′′ [0.87 mm]
13.2′′ [0.65 mm]

Spectral resolution:

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

First light date: 2012
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: see FLASH


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