Welcome to the
Chandra Calibration Database Website
The Chandra X-Ray Center introduced version 4.5.5.1 of the Chandra Calibration Database (CALDB) on 08 Jan 2012.
The CalDB 4.5.5.1 upgrade is a patch upgrade to CalDB 4.5.5. CalDB 4.5.5.1 requires CIAO 4.3 or later version; earlier versions of CIAO do not support recent upgrades to acis_process_events (ACIS subpixel resolution) and hrc_process_events (HRC time-dependent gain maps).
See the CIAO Downloads page for instructions for an automated installation of CIAO 4.5 and CalDB 4.5.5.1 on your local system. Or for manual instructions, see the CalDB Downloads page to install or upgrade your Chandra CalDB to CalDB 4.5.5.1.
CalDB 4.5.5.1 includes the following update:
- ACIS Time-dependent QEU header corrections
See details in the link CalDB 4.5.5.1 Release Notes.
See technical details for all new calibrations released in CalDB 4.5.5 in the link CalDB 4.5.5 Release Notes.
NOTICE to Users: With the advent of CIAO 4.5, the tool mkpsf is no longer supported or included. Hence, the ACIS and HRC PSFLIB hypercube files, nominally stored in ${CALDB}/data/chandra/{acis or hrc}/2d_psf, are becoming obsolete. By the end of the year 2013, the CalDB will no longer maintain these files. Neither will they be indexed for automatic selection from the CalDB.
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:
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Storing and archiving calibration files.
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Maintaining a naming convention and header structure for all calibration files.
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Indexing calibration data, based on FITS header keywords, for software access.
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Permitting updates of calibration data independent of software updates, while maintaining configuration control.
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Providing a traceable history of calibration data in the database by maintaining versioning.
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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.
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