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Last modified: 12 December 2012

URL: http://cxc.harvard.edu/caldb/downloads/Release_notes/CALDB_v4.5.3.html

CalDB 4.5.3 Public Release Notes

Public Release Date: 15 Oct 2012


I. INTRODUCTION

CalDB 4.5.3 is an upgrade to the Chandra CalDB, which includes the following item:

  • ACIS Blank-sky Background files Group E version N0003

For the CIAO 4.4.1 / CalDB 4.5.3 release notes see How CalDB 4.5.3 Affects Your Analysis.

II. SUMMARY OF CHANGES

A. ACIS Blank-sky Background files Group E version N0003

Location: $CALDB/data/chandra/acis/bkgrnd
Filenames: acis2sD2005-09-01bkgrndN0003.fits
acis3sD2005-09-01bkgrndN0003.fits
acis5sD2005-09-01bkgrndN0003.fits
acis6sD2005-09-01bkgrndN0003.fits
acis7sD2005-09-01bkgrndN0003.fits
acis8sD2005-09-01bkgrndN0003.fits
acis0iD2005-09-01bkgrnd_ctiN0003.fits
acis1iD2005-09-01bkgrnd_ctiN0003.fits
acis2iD2005-09-01bkgrnd_ctiN0003.fits
acis2sD2005-09-01bkgrnd_ctiN0003.fits
acis3iD2005-09-01bkgrnd_ctiN0003.fits
acis3sD2005-09-01bkgrnd_ctiN0003.fits
acis5sD2005-09-01bkgrnd_ctiN0003.fits
acis6iD2005-09-01bkgrnd_ctiN0003.fits
acis6sD2005-09-01bkgrnd_ctiN0003.fits
acis7iD2005-09-01bkgrnd_ctiN0003.fits
acis7sD2005-09-01bkgrnd_ctiN0003.fits
acis8sD2005-09-01bkgrnd_ctiN0003.fits

The above files are the newly RE-corrected versions of the Group E ACIS blank-sky background files labeled collectively as "Group E" because they are the fifth grouping, and are the most recently applicable, becoming effective on 2005-09-01T00:00:00. In CalDB 4.5.2, an update to all eighteen of these files had been released, to correct a header error. However, the version N0002 of these BKGRND files had still another error, namely that the GTI extensions were absent, and instead a second redundant EVENTS list was included. This caused extraneous listings of the files in the ACIS CalDB index, and caused acis_bkgrnd_lookup to fail.

The N0003 files above have been generated to correct both the header errors present in the N0001s, and the block structure error of the N0002s.

As with all the ACIS blank-sky BKGRND files, see the ACIS Background Memos web page for more details.

PIPELINES/TOOLS AFFECTED:

reproject_events

THREADS AFFECTED:

Analysing the ACIS Background with the "Blank-Sky" Files


Last modified: 12 December 2012
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