Data Access Policy for ESO Data held in the ESO Science Archive Facility

03 August 2016

The European Southern Observatory (ESO) Science Archive Facility (SAF) has been operational at ESO headquarters in Munich since 1991. It contains data from ESO telescopes at La Silla Paranal Observatory, including the APEX submillimeter telescope on Llano de Chajnantor. In addition, it contains the UKIDSS/WFCAM data obtained at the UK Infrared Telescope facility in Hawaii, as well as the science data products from the ESO/GTC large programmes.

The Principal Investigators (PIs) of successful proposals for time on ESO telescopes, and their delegates, have exclusive access to their scientific data for the duration of a proprietary period. The proprietary period of raw data expires one year after the data files have been made available for download from the ESO SAF to the PI.

The information contained in the headers of all the data files in the ESO SAF is publicly and immediately available. At the end of the proprietary period, the science data products become publicly available. The abstracts of successful proposals are made public as well at the time the proprietary period expires. All calibration data are public immediately after the observations.

Exceptions to the above rules, such as the extension of the proprietary period or restrictions to the access to header information, may be granted in special cases. The corresponding requests have to be justified in detail and submitted to the Director General of ESO for approval. Deviations from the general policies may also occur for Guaranteed Time Observations (GTO). Please check the dedicated information at the GTO policy page.

Some ESO programmes may involve proprietary periods that are specialized to specific programme needs and scientific aims (e.g. immediate international public release). These special cases are documented through the main ESO archive interface.

The public partition of the ESO archive is accessible to all users from the international community. All data in the ESO archive retain ESO’s copyright, and are distributed according to the terms of the Creative Commons Attribution 4.0 International license (CC BY 4.0). ESO reserves the right to restrict or enhance access to the data at any time, in accordance with the VLT/VLTI Science Operations Policy as defined in the 104th Council document (2004).

When downloading data from the SAF, all users are requested to limit the request to maximum five concurrent downloads. Large download requests (over 400 GB) can be made using the media creation facility.

Requirements for third parties distributing ESO data

ESO data files (both raw data and science data products) may be distributed by third parties, and disseminated via other services, according to the terms of the Creative Commons Attribution 4.0 International license. Credit to the ESO provenance of the data must be acknowledged, and the file headers preserved.

In case of scientific use of the ESO data by users that access ESO data via third party archival services, the users should follow the same acknowledgement policies as for the ESO SAF, as described below.

Acknowledgement policies

If the access to the ESO SAF services was helpful for the users’ science work, the following acknowledgement is recommended:
This research has made use of the services of the ESO Science Archive Facility.

All users of the ESO SAF are required to acknowledge the source of the data with an appropriate citation in their publications. Publications making use of ESO observational data must include the following statement in a footnote or in the acknowledgement:

Based on observations collected at the European Southern Observatory under ESO programme(s) TP.C-NNNN(R)1 or PPP.AAAA.nnn2

Publications making use of the ESO SAF, for raw data or science data products, must include the following statement in a footnote or in the acknowledgement:

Based on data obtained from the ESO Science Archive Facility under request number <request_number>.

Publications making use of APEX observational data must include the following statement in a footnote or in the acknowledgement:

Based on observations with the APEX telescope. APEX is a collaboration between the Max-Planck-Institut für Radioastronomie, the European Southern Observatory, and the Onsala Observatory.

For scientific institutions distributing further ESO raw and/or data products:

Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme(s) TP.C-NNNN(R)1 or PPP.AAAA.nnn2, and/or data products created thereof.

All users are kindly reminded to notify Mrs. Grothkopf (esodata at upon acceptance or publication of a paper based on ESO data, including bibliographic references (title, authors, journal, volume, year, page-numbers) and the programme ID(s) of the data used in the paper.

(1) Please substitute the place-holder TP.C-NNNN(R) with the programme ID(s) of the data used, e.g., 094.A-1234(A).

(2) As of ESO period 105 (proposal deadline 26 September 2019, start of operations on 1 April 2020), but also including DDT programmes of period 104, the programme ID format changed to a new simplified structure PPP.AAAA for Programme ID and PPP.AAAA.nnn for run ID, where PPP is Period, and nnn is number of the run, and AAAA is a unique identifier composed of numbers and letters.

You will find the ESO Programme identifier in the FITS header of the observations (under keyword HIERARCH ESO OBS PROG ID for raw data and under keyword PROGIDn for data products). The description of the programme ID syntax is provided in the ESO programme identification code page.