The CALDB is a Unix directory structure containing all the calibration data (ARD) for Chandra, accessed via an index file. The index can be addressed directly by most CIAO tools without the user having to know the location of the exact calibration file they need. In some cases, calibrations require user input, where automatic index searches have not been implemented. Some calibrations need a user choice to be made which the index cannot handle.

All CALDB files follow the standard OGIP file format. An outline of the Chandra CALDB contents is given on the CALDB Files web page.

See the CALDB website for more information on the CALDB.