README File for CALDB 4.7.8 Upgrade Only Instructions 01 March 2018 DE Graessle, Chandra CALDB Manager Includes brief Intro, Upgrade download and installation instructions, and pointers for further assistance. To learn more about the Chandra CALDB, and to find this information on the WEB, you are referred to http://cxc.harvard.edu/caldb/index.html. For Release Notes to the Chandra CALDB4, and specifically CalDB 4.7.8, see http://cxc.harvard.edu/caldb/downloads/releasenotes.html CalDB 4.7.8 requires CIAO 4.5 (or later version) because of an upgrade to the caldb4 software that was included since the release of CIAO 4.5 in December of 2012. The caldb4 upgrade in question provides for the proper selection of time-displaced CalDB files with overlapping validity date ranges, which does not exist in earlier CIAO versions. CalDB 4.7.8 is optimized for CIAO 4.8 (or later version) which includes an upgrade to the acis_process_events tool for handling CC-mode observations, specifically to perform the CTI-correction properly for them. As a result, the EDSER SUBPIX algorithm is now applied in a-p-e to CC-modes, where it had not been before. These instructions apply only to those wanting to upgrade their CalDB version 4.7.3 or later version to version 4.7.8 quickly, installing only the updated calibration files and index updates. You must have installed CalDB 4.7.3 or later version previously, or this upgrade installation will not work correctly. Be sure to use the CIAO command "check_ciao_caldb" to verify your CalDB version before proceeding with these instructions. Condensed Release Notes for CalDB 4.7.8 ------------------------------------------------------------------------------------------ I. INTRODUCTION CalDB 4.7.8 is an upgrade to the Chandra CalDB, which includes the following items: * ACIS T_GAIN Epochs 71+72 updates * HRC-S GAPLOOKUP table version N0004 * Retired 2016 provision T_GAIN files For the CIAO 4.9 / CalDB 4.7.8 release notes see How CalDB 4.7.8 Affects Your Analysis. ------------------------------------------------------------------------------------------ II. SUMMARY OF CHANGES A. ACIS T_GAIN Epochs 71+72 Updates Location: $CALDB/data/chandra/acis/t_gain/ Filenames: acisD2017-05-02t_gainN0005.fits acisD2017-05-02t_gainN0006.fits acisD2017-11-01t_gainN0002.fits acisD2017-11-01t_gain_biN0002.fits The ACIS Calibration team has released new time-dependent gain corrections derived from the External Calibration Source (ECS) during quarterly Epochs 71 (Aug-Oct 2017) and 72 (Nov 2017 - Jan 2018), which have been combined to obtain sufficient counting statistics. With this release, the combined epoch 69+70 CalDB files may be finalized. Users with observations taken between (DATE-OBS=) 2017-05-02T12:00:00 and 2017-11-01T00:00:00 are advised to reprocess with their data with finalized versions of the applicable T_GAIN files. Users with observations taken since 2017-11-01T00:00:00 will have access to an updated provisional T_GAIN file (one of the version N0002 filenames above); They will not however have a finalized file until after Epoch 74 (May-July 2018) is completed. For basic information concerning the ACIS Time-dependent Gain Correction, See ACIS Time-dependent Gain why page. For a more detailed explanation, see the Technical Details section below. PIPELINES/TOOLS AFFECTED: ACIS Level 1 pipeline tool acis_process_events. CIAO script chandra_repro uses acis_process_events to reprocess ACIS observation data. THREADS AFFECTED: Reprocessing Data to Create a New Level=2 Event File B. HRC-S GAPLOOKUP Version N0004 Location: $CALDB/data/chandra/hrc/gaplookup/ Filename: hrcsD1999-07-22gaplookupN0004.fits The CXC HRC-S calibration team has released a correction to the existing GAPLOOKUP table version 3 in the CalDB (released in 27 June 2012 with CalDB 4.5.0), which had a small offset in positions of photons near the aimpoint. This new version N0004 degap file listed above rectifies the issue, by including a shift of +2.5 pixels (approximately 0.018 Ang) to all degap corrections (in CRSV) near the aimpoint position. The new degap solution ameliorates a wavelength shift as seen from tests run on Capella LETGS+HRC-S observations. A full explanation of the new degap correction is given one the HRC Calibration Web page at DEGAP Update for HRC-S2 See the why page for more information on the degap solution in general. For details on this newest GAPLOOKUP table release, see the HRC-S DEGAP Technical Details section below. PIPELINES/TOOLS AFFECTED: Standard HRC Level 1 Data Processing pipeline tool hrc_process_events CIAO script chandra_repro, which uses hrc_process_events to reprocess HRC observation data. THREADS AFFECTED: Reprocessing Data to Create a New Level=2 Event File C. 2016 T_GAIN Provisional Files RETIRED Location: $CALDB/data/chandra/acis/t_gain/ Filenames: acisD2016-02-01t_gain_biN0002.fits acisD2016-02-01t_gainN0002.fits acisD2016-11-01t_gain_biN0002.fits acisD2016-11-01t_gainN0002.fits The above provisional files (flat, non-interpolating) are being deleted from the CalDB distribution with version 4.7.8, and removed from the CalDB ACIS branch index file. These have been in CalDB distribution for more than one year. If users' data file headers show this file as the TGAINFIL value, we suggest they use an upgraded CalDB such as the current release to reprocess their data with the appropriate permanent (finalized) T_GAIN CalDB file for their particular datasets. PIPELINES/TOOLS AFFECTED: None. THREADS AFFECTED: None. ---------------------------------------------------------------------------------- III. Instructions for installing the upgrade from CalDB 4.7.3 or later version to 4.7.8. The following are manual installation instructions. You may also download and install CalDB 4.7.8 using the "ciao-install" script at http://cxc.harvard.edu/ciao/download/, or follow the instruction at http://cxc.cfa.harvard.edu/caldb/downloads/index.html. Before you begin, you must have write privileges in your local CalDB area. If you don't have your system administrator do this upgrade! A. As system admin, verify your current CalDB version. With CIAO installed and loaded, enter the command "check_ciao_caldb" If you do not see that the CalDB version is 4.7.3 or later version, you need to use the MAIN CalDB download procedure from Table 1 of the CIAO CalDB downloads page. If the version shown is 4.7.3 or later, proceed with the following: B. Downloading Instructions: Set your working directory to $CALDB, and verify that you are there. Please download the "upgrade" tar ball and either or both of the other tar balls you may need (as indicated below) into the $CALDB area. The following FTP links will allow you to access the files from the Chandra Data Archive. You may also use your web browser to locate the CalDB Download instructions, and proceed from there: http://cxc.harvard.edu/caldb/downloads/index.html CALDB UPGRADE FILE: ftp://cda.harvard.edu/pub/arcftp/caldb/upgrade/caldb_4.7.8_upgrade.tar.gz The ACIS BKGRND files have been updated to include (1) eleven N0002 files in Group G for 2012-01-01 through the present. Added as of the release of CalDB 4.7.6 on 18 Aug 2017. ftp://cda.harvard.edu/pub/arcftp/caldb/acis_bkgrnd_4.7.6.tar.gz Three new HRC-I BKGRND files, effective for calendar years 2015-2017 respectively, have been added to the CalDB as of version 4.7. (14 Dec 2017). As has been the case since their original addition to CalDB, they are packaged separately in the following tar file: ftp://cda.harvard.edu/pub/arcftp/caldb/hrc_bkgrnd_4.7.7.tar.gz TABLE 1: Files, sizes, and md5sum values: FILENAME Ship Size Unpacking space md5sum (bytes) caldb_4.7.8_upgrade.tar.gz 465,490,174 2.8 GB 51df73cef70db7081c2654583bc26425 acis_bkgrnd_4.7.6.tar.gz 1,387,251,364 2.9 GB 192d4871813c9d5d3e857726195d1261 hrc_bkgrnd_4.7.7.tar.gz 2,323,747,030 3.2 GB 3c9b4e5d6966929793d726b12ae4a4b2 C. Unpacking instructions: We prefer that you use gtar with the appropriate options to unzip and untar the files in a single step, to save disk space and to apply the safest unpacking procedures: gtar xvUfz caldb_4.7.8_upgrade.tar.gz gtar xvfz acis_bkgrnd_4.7.6.tar.gz gtar xvfz hrc_bkgrnd_4.7.7.tar.gz LINUX users: You may omit the "U" uption in the first gtar command. D. Upgrade verification checks See the CalDB downloads web page for steps to verify your upgrade installation, at http://cxc.harvard.edu/caldb/downloads/index.html#dl_config. - Dale Graessle Chandra CalDB Manager