CALDB PUBLIC RELEASE NOTES

VERSION 2.23
CALDB EFFECTIVE DATE: 2003-06-30T00:00:00

PUBLIC RELEASE with CIAO 3.0 2003-08-06T18:00:00
INSTALLATION in SDP: 2003-07-01T17:00:00

I. Summary of Changes

A. Reordering of acis7sD2000*bkgrndN0002.fits files in the ACIS CALDB
index.

Relevant files:
acis7sD2000-01-29bkgrndN0002.fits
acis57sD2000-01-29bkgrndN0002.fits
acis7sD2000-12-01bkgrndN0002.fits
acis57sD2000-12-01bkgrndN0002.fits

The ACIS CALDB index has been reordered, to include the above
files in the above order, rather than that order reversed as it
had been in the CALDB 2.22 release. The result is that the
acis_bkgrnd_lookup command:

acis_bkgrnd_lookup infile=<your filename> chipids=7 aimpoint=s

will now return one of the acis7sD2000*bkgrndN0002.fits files
rather than one of the acis57sD2000*bkgrndN0002.fits files.
The acis7s* files are larger datasets, particularly in the 2000-12-01
case, and are preferable for chip ACIS-7 data. For those who wish
to use common background sets between ACIS-5 and ACIS-7, you may
still select the acis57s files by means of

acis_bkgrnd_lookup infile=<your filename> chipids=5 aimpoint=s

The relevant thread here is:
"ACIS Background Subtraction (Blank-Sky Files)"
http://cxc.harvard.edu/ciao/threads/acisbackground/


B. Null-effect CONTAM placeholder file
Location $CALDB/data/chandra/acis/bcf/contam	(New directory)
Filename: acisD1999-08-13contamN0000.fits

This file allows CIAO 3.0 ARDLIB to function properly in
lieu of a viable time-dependent ACIS OBF contamination
correction file. ARDLIB has been modified to include a
uniform time-dependent modification of the effective QE.
However the calibration data for this function has not been
approved for release.

The default for CIAO currently is that no adjustment is made
for the time-dependent effective QE for ACIS due to the
buildup of contamination on the optical blocking filters.

Affects CIAO tools: mkarf, mkinstmap, mkgarf

See the CIAO 3.0 web page
"Using the ACIS Contamination File"
http://cxc.harvard.edu/ciao3.0/threads/aciscontam/
for details on the existing means to modify exposure
maps, ARFs, or GARFs to account for the known time
dependence in the QE.


C. PCAD IRU Characteristics file, version 2
Location: $CALDB/data/chandra/pcad/bcf/iru/
Filename: iruD1999-08-12charN0002.fits

Standard Data Processing ONLY. ASPECT L1 processing.

This file does NOT affect CIAO 3.0 in any way.

The new file includes the appropriate information for
IRU-B.

Changed values of config2_chan column from [4 5 6 7] to [5 4 7 6]. 
This is needed to create the correct mapping between physical gyro 
axes (spec'd in the corresponding values of gyro_sc_align) and gyro 
count telemetry MSIDs AOGYRCT<1-4>.