Last modified: May 2019

AHELP for CIAO 4.11


Context: tools


Run CIAO tasks from the ds9 Analysis menu


A number of common CIAO tasks are available from the ds9 Analysis menu. This menu addition allows users to get source counts, smooth an image, and create a histogram - among many other things - from the ds9 program in CIAO. The analysis menu tasks are known as "dax" (ds9 analysis extensions).

Getting Started

The commands are stored in the file $ASCDS_INSTALL/contrib/config/ciao.ds9 and are automatically loaded when ds9 is launched within CIAO.

The user can also explicitly point to the file in the ds9 -analysis switch:

unix% ds9 -analysis $ASCDS_INSTALL/contrib/config/ciao.ds9 ...

Using the Tools

Under ds9's Analysis menu, at the bottom will be a "CIAO tools (DAX)" option. Selecting "CIAO tools (DAX)" will display the category of CIAO tasks :

Calculating the Statistics

The options under the Statistics item use the combination of all defined regions to calculate the quantities. To exclude certain areas, define a region and use the "Region -> Properties" menu to set it to "exclude". If no regions are defined, the calculations are run on the entire image created at the current binning value.


Plotting is done using the built in ds9 "BLT" plotting package. User can use the menu bar on the plot window to change the axes to log scale, change fonts and colors, etc.

Changes in the 4.11.3 (May 2019) release

This release includes major changes to dax affecting most of the individual analysis tasks.

Output Files

Users can now select the directory where they want the DAX output file to be written. There is a new dax.par parameter file where users can specify the default output directory, outdir. Alternatively, user can set the DAX_OUTDIR environment variable, or they can change the output directory via the new 'Change DAX output directory' analysis task.



All of the histogram plots are now created using ds9 built-in "BLT" plotting package. Users can use the options in the menu bar to save (print) the figure and adjust the plot style (linear|log, fonts, colors). All of the tasks also now save the output file in the DAX_OUTDIR (as discussed above).





Image Processing

Change DAX output directory

New task to allow users to change DAX output directory during the current analysis session. The directory selected is not saved. Use

pset dax outdir=directory

to permanently change the output directory.

Changes in the 4.11.1 (December 2018) release

Clarified error messages to indicate that users must have regions selected to perform spectral or spatial fits. Additional internal changes to use python scripts to perform sherpa fits rather than using sherpa IPython wrapper.

Changes in the 4.10.3 (October 2018) release

Updated to ensure that on systems where ds9 autoloads funtools or zhtools analysis tools, that it is still able to start the chipsServer in the background.

Internal updates to support ds9 v8.

Change in the 4.8.4 (September 2016) release

Several tasks have been updated to ensure that the desired region format is retrieved from ds9 instead of relying on the assumed defaults.

Changes in the 4.6.7 (November 2014) release

A new "Net Counts" option has been added that emulates the FUNTOOLs 'Counts in a region' functionality. This provides net counts and rates individually for each region.

The Aperture Photometry task has been renamed and moved. It is now available as the "Statistics -> Photometry (srcflux)" task.

The "All" statistics have been renamed "dmstat" to make it more clear which task is being run.

About Contributed Software

This script is not an official part of the CIAO release but is made available as "contributed" software via the CIAO scripts page. Please see this page for installation instructions - such as how to ensure that the parameter file is available.

Known Limitations


See the CIAO website for an up-to-date listing of known bugs.

Refer to the CIAO bug pages for an up-to-date listing of known issues.