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Welcome to the “Centre d'Analyse de Données Etendues” (CADE) or “Analysis Center for Extended Data”. CADE provides maps of ancillary astronomical data to the users of the astronomical community. The emphasis of CADE is on the extended sky emission. The database is provided in the HEALPix sky pixelization scheme.

An increasing number of large survey projects uses an unique hierarchical pixelization of the celestial sphere called HEALPix. A strategy of ancillary data ingestion in the HEALPix format is used, which allows to generate partial or all-sky HEALPix files from the more traditional local representation traditionally used for astronomical data. The ingestion tool is based on the drizzling library, and uses a strategy where the surface of pixel intersection is computed as presented in Appendix A in Paradis et al., 2012, A&A, 543, 103. The method allows fast ingestion and guarantees the photometric accuracy of the transformation with minimal data loss during the transformation from local FITS maps in the WCS (World Coordinate System) system to HEALPix.

CADE ensures the data production in the HEALPix maps, data archiving and diffusion to the community.

The service delivers

  • A set of extended data maps in the HEALPix format for various astronomical large-scale surveys.
  • Meta-data that facilitates automated data analysis.
  • Non-publicly available surveys, used by some projects (including Planck, Herschel).
  • VO compatible data, accessible through the Aladin software (
  • The drizzling library allowing for data projection from HEALPix to local WCS, available here :

Future developments

  • Uncertainty and/or hit count maps will be associated to the data
  • Additional meta-data will be included in the header of the files
  • Tool: SED extractor, compatible with the DustEM software

People involved

If you have any questions or comments, please contact :

We thank Pierre Fernique, Laurent Cambrésy, Caroline Bot, Thomas Boch, Jean-Michel Glorian and Antoine Goutenoir for their help.