Welcome to the
Chandra Calibration Database Website
The
Chandra X-Ray Center introduced
version 4.1.2 of the Chandra Calibration
Database (CALDB) on 27 MAR 2009.
CALDB 4 is a brand new, newly-configured, newly-supported
calibration database for Chandra, in particular for CIAO 4.1.
The directory structure, caldb configuration (index files),
and the software interface are all changed/upgraded.
The CalDB 4.1.2 upgrade is a small patch to
CalDB 4.1.0 and 4.1.1. It includes the following items:
- ACIS T_GAIN updates for Epoch 36, Nov 08 thru Jan 09.
- Minor corrections to the first extension header of each of
the two ACIS CTI N0005 files, so automatic selection by
acis_process_events will work better.
- A change to the Calibration Validity Start Date and Time
for the -110C ACIS calibration files in CalDB. This affects
only one OBS_ID (62538, HR1099, HETG/ACIS-S) from early in the
mission.
Users are strictly cautioned that CalDB 4.1.2 is totally
incompatible with CIAO 3.4. CalDB 4.1.2 is required by CIAO 4.1
and later versions, but will not work at all if you install it
with or in CIAO 3.4.
See details in the link CalDB
4.1.2 Release Notes.
CalDB version 3.5.3, for use only with CIAO3.4, is still
maintained by the CXC, and may be accessed and downloaded from
the CALDB3 main and download
pages. Compatible upgrade
files will be added to CalDB 3.5.3 for at least throughout
calendar year 2009. See the caldb3 web page for details and
upgrades for CalDB 3.5.3.
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.
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