Welcome to the
Chandra Calibration Database Website
The Chandra X-Ray Center has introduced version 184.108.40.206 of the Chandra Calibration Database (CALDB) on 09 July 2020.
See the CIAO web page for links to instructions using ciao-install or Conda for an automated installation of CIAO 4.12 and CalDB 220.127.116.11 on your local system. Or for manual instructions, see the CalDB Downloads page to install or upgrade your Chandra CalDB to CalDB 18.104.22.168.
As of 2:00 PM EDT on 14 July 2020 (UTC 2020-07-14T18:00), a revision has been made to the CalDB 22.214.171.124 upgrade tar file, which may be accessed manually on the Download CalDB 126.96.36.199 web page, or installed automatically using ciao-install. Details are given at that link to determine if you might have been affected by a tar file unpacking error, and how to fix the resulting problem, if you upgraded your CalDB with ciao-install before that date.
CalDB 188.8.131.52 is compatible with CIAO 4.12 and later versions ONLY! Please do not attempt to upgrade your CalDB for CIAO 4.11 or older versions with CalDB version 184.108.40.206. None of the ACIS upgrades in CalDB 220.127.116.11 will be applied with the older software because of required software changes to do so. Furthermore, the HRC-S chip edge offset values will not be applied in CIAO 4.11 with CalDB 18.104.22.168, and users will not be notified by the software if this occurs.
As a result of this, there will be no further CalDB upgrades provided for CIAO 4.11 or CIAO 4.10.
CalDB 22.214.171.124 includes the following updates:
- FULL ACIS T_GAIN Library Upgrade, Epochs 1-80
- ACIS FP_TEMP Boundary Condition Extensions for currently applicable files
- HRC-S T_GMAP Upgrade version N0003
- HRC-S QE version N0015 upgrades
- HRC-I QE version N0012 upgrades
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:
Storing and archiving calibration files.
Maintaining a naming convention and header structure for all calibration files.
Indexing calibration data, based on FITS header keywords, for software access.
Permitting updates of calibration data independent of software updates, while maintaining configuration control.
Providing a traceable history of calibration data in the database by maintaining versioning.
Translating calibration products into formats suitable for processing and/or analysis.
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.