How This Cookbook Works

Each of the following subsections describes a single step of processing. Each section begins with an explanation of what the step actually does, and then describes the commands that must be run to accomplish that step. This description is followed by a discussion of the output products. As many of the outputs are diagnostic, we attempt to explain how to use them. Many of the diagnostic files are not needed for further processing and can be deleted or saved elsewhere.

There are a number of different conventions for naming the individual CCDs of the MOS instruments. We will refer to the $n^{th}$ chip of MOS$M$ as MOS$M$-$n$. There are twelve pn CCDs but ESAS does not treat them separately, only as quadrants, which are sets of three CCDs. These are labeled in Figure 1.

In this document when examples of task calls are provided they are broken into multiple lines for clarity. When actually invoking a task all parameters should be on one line (or the lines should be ended with the proper continuation character). In the appendices, long single line commands are broken, and the continuation lines are indented. This is to make it difficult to cut and paste from the cookbook to the command line. A version of the main reduction script where the command lines are unbroken can be found at

Many of the commands have input parameters with sensible defaults. For the most part, when giving example commands, we will not list parameters with sensible defaults.

We note, and apologize for, having said the same thing multiple times in different places. We understand that users may dip in and out of the cookbook as they run into problems. We can't count on the reader having read just the right part of the preceding material that is necessary to understand the current material. Thus the repetition!