Phase 3

17 November 2015

  • First release of multi-band source catalogue data resulting from the VST Public Survey ATLAS published [Read More]

16 September 2015

  • New release of stacked reduced images and source lists for the VST Public Survey ATLAS [Read More]

21 August 2015

  • New Data Release of VVV Photometric Catalogues [Read More]

6 August 2015

  • New Release of PESSTO Spectroscopic Public Survey Data [Read More]

[More News...]

In a nutshell, Phase 3 denotes the process of preparation, validation and ingestion of science data products (SDPs) for storage in the ESO science archive facility, and subsequent data publication to the scientific community. SDPs are produced by 1) principal investigators of ESO observing programmes, and 2) ESO pipelines as part of the quality control (QC) process or from specific, dedicated, re-processing projects for homogeneous raw data sets.


ESO’s policies governing Phase 3 are specific to the type of observing programme. Phase 3 is mandatory for ESO Public Surveys and for ESO Large Programmes since period 75. For other ESO programmes there is no obligation but PIs are invited to take advantage of the Phase 3.

To ensure the successful integration of SDPs into the archive, ESO supports the users in carrying out the Phase 3 process by defining ESO/SDP data standards, by devising procedures and providing the infrastructure for the delivery of SDPs, and by supplying tools for the data preparation.

The description of the policies, the data standard and the procedure for the submission of reduced data products applicable to the ESO Phase 3 process given here is intended to provide the information for the preparation and successful completion of the ESO Phase 3 process.

The target audience consists of 1) principal investigators and their collaborators who return reduced data products resulting from ESO observations for public release to the astronomical community through the ESO archive, 2) ESO scientists involved in the QC process or in specific re-processing projects, 3) instruments scientists and pipeline developers for the new and existing ESO instruments.

In March 2011, Phase 3 operations have started to support the validation, transfer and publication of the first data products from ESO public surveys. Other ESO observing programmes will be handled through the Phase 3 system as soon as the underlying data products standard and infrastructure have been extended to cover the respective instruments and data product types.

Contact the Phase 3 Helpdesk

For any questions regarding Phase 3, its policies, the data content and format, or the submission process of data products to the ESO Archive, please feel free to contact the ESO Archive Science Group via email at, subject: Phase 3