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Last modified: 29 August 2012


CalDB Release Notes

Internal Only -- Not For Public Release

SDP Installation Date: 2012-08-09T17:00:00 (UTC)


CalDB is an internal-only upgrade to the Chandra CalDB, which includes the following items:

  • Correction to 2012-03-29 HRC-S T_GMAP Cal Validity End Date
  • Correction to 2011-08-01 ACIS T_GAIN Cal Validity End Date

The updates in CalDB are minor, and only affect the DS 8.4.5 software.


A. Correction to 2012-03-29 HRC-S T_GMAP Cal Validity End Date

Location: $CALDB/data/chandra/hrc/t_gmap/
Filename: hrcsD2012-03-29t_gmapN0002.fits

A problem in the CalDB file search for HRC-S GTI_LIM files turned up with the release of CalDB 4.5.1. The specific error occured in that the wrong GTI_LIM file was being selected for DATE-OBS later than 2002-11-15T00:00:00, in the MTL L1 pipeline. A bug has been found in the DS 8.4.5, which is triggered when a file is listed in CalDB that includes a Cal validity End Date (CVED), but not a Cal Validity End Time (CVET). In CalDB 4.5.1, there was one such new entry, specifically with the T_GMAP file named above. To fix the problem in the near term, this trigger was removed from the HRC-S branch index file, by removing the CVED0001 keyword from the named T_GMAP file, and rebuilding the index.


Mission timeline level 1 (MTL_L1) pipeline in SDP is affected, which calls for the HRC-S GTI_LIM pipeline, and derives the GTIs for the HRC Level 1 events file. Note that the HRC L1 pipeline, which calls for the T_GMAP, is unaffected by the error, or by this correction.

B. Correction to 2011-08-01 ACIS T_GAIN Cal Validity End Date

Location: $CALDB/data/chandra/hrc/t_gain/
Filenames: acisD2011-08-01t_gainN0006.fits

With CalDB 4.5.0, the CVED0001 and CVET0001 keyword values of the ACIS T_GAIN files named above were corrected by an automated procedure, to fix the T_GAIN selection for OBS_ID 13535. (See the CalDB Caveat Page 38 ACIS OBS_IDs with "Problem Reading TGAINFILE".) However, the CalDB manager also manually updated the CVED0002 keyword manually to keep it consistent with CVED0001, but he mistyped the year value as "2012" instead of "2011". This caused the file to be selected incorrectly for all 23 of the ACIS CTI radiation zone ERs that were processed in AP between the 4.5.1 release date (2012-06-27) and 2012-08-02, when the problem was discovered in SDP AP. Those CTI ERs will be reprocessed with CalDB immediately upon installation of


ACIS Secondary L1 pipeline, specifically tool acis_process_events. The secondary pipeline is called when the OBS_MODE = SECONDARY, which is the case for all of the ACIS CTI radiation zone engineering runs (ERs).