All about APEX data

Do you want to…

… know about APEX data reduction?

The APEX raw data are stored in the so-called MBFITS data format.

For heterodyne observations, these raw data are calibrated online by the apexOnlineCalibrator program, which writes the calibrated spectra (TA*scale) into a CLASS-format data file. The data can be further reduced and analysed using CLASS, GREG, MAPPING programs included in the GILDAS software package.

For bolometer observations you need to work directly on the MBFITS files. There are various packages available for the data reduction of different instruments. We refer you to the page about bolometer data reduction for more specific information.

Related documents


Multi-Beam FITS Raw Data Format (ICD) 1.02 MB 214 downloads

Interface Control Document by D. Muders ...

APEX calibrator and data reduction manual 791.33 KB 298 downloads

by E. Polehampton, H. Hafok and D. Muders ...

…check the calibration of your heterodyne data?

The data observed with heterodyne instruments is provided in CLASS format and is in TA*scale (K).

  • To check for the long-term variations in the calibration of line intensities we maintain a web page with historical measurements of reference sources (assumed to be non-variable). You can access those via our Grafana interface.
  • To convert your line intensities from the antenna temperature (TA*) scale into the main beam brightness temperature scale (TMB) you will need to check the telescope efficiencies. We maintain a list with historical measurements taken with cross-scans on planets.

…publish your research based on APEX data?

We cannot be more happy about that! Please remember that:

  • We request that any publication using APEX data, including the public science verification data, adds the following acknowledgement:
  • For data taken before 2023
    “This publication is based on data acquired with the Atacama Pathfinder Experiment (APEX) under programme ID [TP.C-NNNN(R)]. APEX is a collaboration between the Max-Planck-Institut fur Radioastronomie, the European Southern Observatory, and the Onsala Space Observatory.” If your data is obtained during Swedish time, please add “Swedish observations on APEX are supported through Swedish Research Council grant No 2017-00648“.
  • For data taken after 2022 add in the acknowledgments:
    “The data was collected under the Atacama Pathfinder EXperiment (APEX) Project, led by the Max Planck Institute for Radio Astronomy at the ESO La Silla Paranal Observatory.”
  • After you publish, we encourage you to provide your reduced and calibrated data to the ESO archive through the Phase 3 system. Providing your reduced data to the community facilitates other ESO archive users to reuse your dataset and at the same time disseminating and referring to your work.

…access archival APEX data products?

All APEX data before 2023 are stored in the ESO archive and most of them become public after some proprietary period. Check here more information about what data is available, the different rules for proprietary periods and how to access APEX data.