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Last modified: 17 April 2024


Welcome to the
Chandra Calibration Database Website

The Chandra X-Ray Center has introduced version 4.11.1 of the Chandra Calibration Database (CALDB) on 18 April 2024.

CalDB 4.11.1 has been released, for use in CIAO 4.16, and users are encouraged to download both using the Conda or ciao-install procedures.

CalDB 4.11.1 is only compatible with CIAO 4.16.0 or later versions! CIAO 4.14-4.15 may use CalDB versions 4.9.0 through 4.10.7. An error in acis_process_events will occur with CalDB 4.11.0 using CIAO 4.14 or 4.15, due to the new ACIS CTI N0012 files format changes.

See the CIAO web page for links to instructions using either Conda, or the new upgraded ciao-install, for an automated installation of CIAO 4.16 and CalDB 4.11.1 on your local system. Or for manual instructions, see the CalDB Downloads page to install or upgrade your Chandra CalDB to CalDB 4.11.1.

CalDB 4.11.1 includes the following updates:

See details in the links CalDB 4.11.1 Release Notes.

The CALDB is the directory and indexing structure that stores and provides access to all calibration files that are required for standard processing and analysis.

These files are used in standard data processing, as well as for analysis with software packages such as CIAO. When you apply a gain map, create an exposure map, or build response files (RMFs and ARFs) - among many other things - you are using the Chandra CALDB to apply the necessary calibration files.

The CALDB serves many functions:

These webpages contain information about each of these topics. They are also designed to help you (or your system manager) understand how the CALDB is assembled and how it works in the Chandra software system.

Please email the CXC Helpdesk with any questions or comments on the CALDB and this website.