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Last modified: 7 November 2019

URL: http://cxc.harvard.edu/caldb/index.html

Welcome to the
Chandra Calibration Database Website


The Chandra X-Ray Center has introduced version 4.8.5 of the Chandra Calibration Database (CALDB) on 07 NOV 2019.

See the CIAO Downloads page for instructions for an automated installation of CIAO 4.11 and CalDB 4.8.5 on your local system. Or for manual instructions, see the CalDB Downloads page to install or upgrade your Chandra CalDB to CalDB 4.8.5.

CalDB 4.8.5 includes the following updates:

See details in the links CalDB 4.8.5 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.