ALADIN will provide images of the complete sky. These images will allow, when necessary, to perform processing or re-calibrations specifically adapted to the environment of a given object.
Several digitized surveys will be made available at CDS in a near future. The first one is the survey completed at STScI for the needs of HST program (Lasker 1994): the integration of compressed SERC-J (factor 10) into the ALADIN project is expected to take place at the end of 1993, and the integration of compressed POSS-IE (factor 10) at the end of 1994, thus providing a complete, digitized sky for the end of 1994, occupying about 100 GB.
From 1994 on, the CDS will also integrate selected fields provided by the French CAI (MAMA, Guibert 1992). In the future, it is thought to integrate the POSS-II survey digitized by STScI (from 1995), and CCD images generated by the DSS Sloan and LITE projects (from 1998).
The completed interactive sky atlas will require a storage capacity of the order of one Terabyte, for a complete sky coverage (in one color with a resolution of 1 arcsec and coding on 16 bits; this can be less when data compression is used).
CDS was funded by INSU to start the project with a juke-box of 12 inch WORM optical disks, allowing the storage of 520 GigaBytes (ATG-Cygnet JukeBox, with the DOROFILE Unix File system emulation).