Last modified: 22 August 2023

Can I use a newer version of ds9 than the one packaged with CIAO?

In short, yes. There is a simple way to do so and a few important caveats associated with upgrading the imager, all of which are described in this FAQ.

When a CIAO release is being prepared, the most recent version of ds9 available is used in testing and then packaged with the software. Since updates to ds9 are released on a shorter timescale than CIAO, users may wish to upgrade independently of CIAO to take advantage of new features and bug fixes.

The $HOME/.ciaorc file is used to specify the path to a different installation of ds9. The default entry looks like this:

# Replace /usr/local/bin with path to ds9 to force use of local ds9
#DS9 /usr/local/bin

Uncomment the second line and change the path to the location of the newer imager on your system:

# Replace /usr/local/bin with path to ds9 to force use of local ds9
DS9 /your/ds9/path

Then restart CIAO so that the .ciaorc file is read. The new imager is now available to CIAO. To confirm that the new path is being used:


Note: the command "which ds9" will continue to point to /soft/ciao/bin/ds9, which is a wrapper script for the application.


  • We do not guarantee that CIAO will work flawlessly with a newer release of ds9! The software team only tests the version of ds9 included with CIAO; it is possible that subsequent changes to the imager may cause unexpected problems in the CIAO software. Users who experience problems may contact the CXC HelpDesk, and we will do our best to assist you.

  • The preferences set in ds9 are stored in a file called $HOME/.ds9.prf. A preferences file created for an older or newer version of ds9 may cause problems with the ds9 packaged in CIAO. To avoid a possible conflict, delete or rename this file. The Preferences section of the ds9 manual contains more information on avoiding this problem when supporting multiple versions of ds9.

For more general information on how to use ds9, refer to the Using SAOImage ds9 thread.