Hello Chandra Users:
For those of you who have downloaded and installed CalDB 4.5.2 since it
was released on Thursday 9/27/2012:
I regret to inform you all that a local HEAD user has found the updated
Group E ACIS BKGRND files to be in error again, this time causing
*acis_bkgrnd_lookup* to fail, as well as having omitted the GTI
extension that is required in these files for CIAO tool
*reproject_events* to run properly. Hence I've brought more evil upon
you, instead of just fixing the original problem.
We are working to release a properly-corrected set of these files as
soon as possible, but with a more careful internal review, within about
a week.
The updated, but still errant, files release in CalDB 4.5.2 are in
$CALDB/data/chandra/acis/bkgrnd/, and are named specifically
acis2sD2005-09-01bkgrndN0002.fits
acis3sD2005-09-01bkgrndN0002.fits
acis5sD2005-09-01bkgrndN0002.fits
acis6sD2005-09-01bkgrndN0002.fits
acis7sD2005-09-01bkgrndN0002.fits
acis8sD2005-09-01bkgrndN0002.fits
acis0iD2005-09-01bkgrnd_ctiN0002.fits
acis1iD2005-09-01bkgrnd_ctiN0002.fits
acis2iD2005-09-01bkgrnd_ctiN0002.fits
acis2sD2005-09-01bkgrnd_ctiN0002.fits
acis3iD2005-09-01bkgrnd_ctiN0002.fits
acis3sD2005-09-01bkgrnd_ctiN0002.fits
acis5sD2005-09-01bkgrnd_ctiN0002.fits
acis6iD2005-09-01bkgrnd_ctiN0002.fits
acis6sD2005-09-01bkgrnd_ctiN0002.fits
acis7iD2005-09-01bkgrnd_ctiN0002.fits
acis7sD2005-09-01bkgrnd_ctiN0002.fits
acis8sD2005-09-01bkgrnd_ctiN0002.fits
These datasets were applicable for extended source OBS_IDs taken on or
after 2005-09-01, as the filenames indicate. The affected thread is
"Analysing the ACIS Background with the "Blank-Sky" Files", posted at
http://cxc.harvard.edu/ciao/threads/acisbackground/
A notice has been added to the CalDB main web page:
as well as the CalDB 4.5.2 release notes pages:
http://cxc.harvard.edu/caldb/downloads/Release_notes/CALDB_v4.5.2.html
and
http://cxc.harvard.edu/ciao4.4/releasenotes/ciao_4.4.1_release.html#HowCALDB4.5.2AffectsYourAnalysis
indicating the problem.
As always, please contact the CXC HelpDesk with any questions or for
further clarification.
I apologize for any inconvenience this may have caused you!
- Dale Graessle
Chandra CalDB Manager
This archive was generated by hypermail 2b29 : Tue Feb 12 2013 - 01:00:13 EST