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Last modified: 25 Jan 2010
Where are the PDFs?

A Note on Processing Versions

CIAO 4.2 Science Threads


Last Update: 25 Jan 2010 - updated for CIAO 4.2 and CALDB 4.2.0: example of using check_ciao_caldb; screen output of caldb_version.fits


The CIAO Science Threads are designed to work with Chandra data that has been created using recent calibration data. In the past we have referred to this as "reprocessed" data, since early datasets have had to be reprocessed using the new calibration files.


Checking the pipeline version

Sample ObsIDs used: 1843 (ACIS-I, G21.5-0.9); 578 (ACIS-S, 3C 295)

File types needed: evt2

The version naming convention changed after version R4CU5UPD14 to the "DS" system, starting with DS 6.0.0. Any data with a processing version of DS 6.0.0 or higher is more recent than R4CU5UPD14.

The processing version information is stored in the ASCDSVER keyword:

unix% dmkeypar acisf01843N002_evt2.fits ASCDSVER echo+

For an older version of the same dataset:

unix% dmkeypar acisf01843N001_evt2.fits ASCDSVER echo+

Read the Reprocessing Data to Create a New Level=2 Event File thread to see if your data needs to be reprocessed.

Checking the CALDB version

It is also useful to check the version of the CALDB used in processing, since the threads reference the CALDBVER header keyword when discussing processing changes:

unix% dmkeypar acisf01843N002_evt2.fits CALDBVER echo+ 

The CALDBVER header keyword is not updated by the CIAO tools. The value always reflects the version of the CALDB applied in standard data processing (SDP).

To find out which version of the CALDB you are running on your local system, use the check_ciao_caldb script:

unix% check_ciao_caldb
CALDB environment variable = /soft/ciao/CALDB
        which is a link to = /data/CALDB/ciao
             CALDB version = 4.2.0
             release date  = 2009-12-15T17:00:00
CALDB query completed successfully.

CALDB 4.2.0 is installed.

The information is also stored in the caldb_version.fits file:

unix% dmlist "$CALDB/docs/chandra/caldb_version/caldb_version.fits[cols caldb_ver]" data
Data for Table Block CALDBVER


     1 4.1.0
     2 4.1.1
     3 4.1.2
     4 4.1.3
     5 4.1.4
     6 4.2.0

This file is automatically updated each time the CALDB is upgraded on your system, so the final row always indicates the current version.


22 Dec 2004 updated for CIAO 3.2/CALDB 3.0.0
01 Dec 2005 updated for CIAO 3.3/CALDB 3.2.0: screen output of caldb_version.fits
01 Dec 2006 updated for CIAO 3.4 and CALDB 3.3.0: screen output of caldb_version.fits
09 Jan 2008 updated for CIAO 4.0 and CALDB 3.4.2: screen output of caldb_version.fits; ObsID 1843 is now version N002
30 Dec 2008 updated for CIAO 4.1 and CALDB 4.1.0: screen output of caldb_version.fits
25 Jan 2010 updated for CIAO 4.2 and CALDB 4.2.0: example of using check_ciao_caldb; screen output of caldb_version.fits

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Where are the PDFs?
Last modified: 25 Jan 2010