There are currently over 100 threads available from the CIAO web pages (106 at the writing of this article). The threads simply show how to perform a certain task, often without explaining why it is important or where it falls into the larger analysis session. To address these issues we are working on building inter-connected web pages. Two new types of documents have been created: analysis guides and why? topics.
Looking at the large amount of documentation online, it can be difficult for a new CIAO user (or even an experienced one!) to know where to start. The analysis guides serve as a "roadmap" through the threads. Each guide takes a certain instrument configuration (e.g. ACIS) or type of analysis (e.g. extended sources) and lists the relevant threads. Along with the listing is a brief explanation of the purpose of each task, as well as the specific order in which they should be run, if any. The goal is to help the user to complete the analysis without requiring that every CIAO thread be read. Three analysis guides are now available, and several more are planned for the near future.
On the other hand, the threads sometimes do not contain enough information for the scientist interested in the details. Just as the analysis guides create a layer above the threads, the why? topics are intended to dig deeper. Some of the topics describe aspects of the Chandra Observatory and data obtained with it, while others provide information on why certain science decisions are made.
There are six why? topics online at the moment and over a dozen more have been requested.
All of this information combined - the guides, threads, and why? topics - enable the user to tailor the analysis to a particular dataset or scientific goal.
At present, the analysis guides and why? topics are largely available only from their respective index pages. The infrastructure of the threads is being modified and improved for the CIAO 3.0 release (scheduled for Summer 2003) to incorporate all of these references. At that time, there will also be a major effort to include links to relevant Proposers' Observatory Guide sections from the threads.
The documentation team is always interested to receive feedback from the users on what information is particularly useful and which areas are lacking. We encourage you to send comments and suggestions for improvement via the CXC Helpdesk.
Related online references:
The main CIAO webpage
http://chandra.ledas.ac.uk/ciao/ (UK mirror site)
Please send questions and comments on CIAO and the documentation to the CXC Helpdesk
Elizabeth Galle and Antonella Fruscione, for the CIAO documentation team