Last modified: 12 December 2023

What is a "standard" CIAO installation?

The CIAO threads assume that all of the "standard" CIAO components have been downloaded and installed: tools, Sherpa, the Scripts Package, and the CALDB.


The prism package was removed in CIAO 4.14.

If you have installed a customized version of CIAO, it is possible that some of the analysis tasks will fail due to a missing package. Similarly, the scripts may contain a dependency on any of the other standard components, and will fail if one is missing.

The way that CIAO is split up into packages depends on how CIAO was installed
Installation Area Packages
conda executables ciao, ciao-contrib, ds9, marx, sherpa
CALDB caldb, caldb_main, acis_bkg_evt, hrc_bkg_evt
ciao-install executables core, graphics, tools, obsvis, sherpa
CALDB CALDB_main, CALDB_acis_bkgrnd, CALDB_hrc_bkgrnd

You do not need all these packages to use CIAO; in particular the CALDB packages are no always needed (and you can use the download_obsid_caldb script to download a subset of the CALDB just for the Chandra data you wish to a analyze).