12 Introduction

This part of the cookbook provides a set of simple recipes for performing various parts of the photometric calibration process. The recipes are widely applicable and straightforward to follow. However, they are not appropriate if very-high-precision results are required. The recipes are:

The recipes are independent of each other; you can simply choose the ones which are appropriate for your purposes. Many different packages for performing photometry are available and they have different strengths and weaknesses. The recipes in this cookbook use the following packages:

for aperture photometry (see SUN/45[22]),
an interactive image display tool with facilities for aperture photometry (see SC/17[17] and SUN/214[20]),
a set of general image-display and manipulation utilities (see SUN/95[11]),
for manipulating catalogues and tables (see SUN/190[16]).

These items should all be available at all Starlink sites. If you have any difficulty in running them then see your site manager in the first instance. To run the recipes you should use a display capable of receiving X-output (typically an X-terminal or a workstation console). Strictly speaking the software will run on a black-and-white device, but realistically you need a colour display. Before starting you should ensure that your display is configured to receive X-output.

The recipes simply show you how to use the packages for a set of specific purposes. In all cases the packages have additional features which are not described here. You should see the appropriate user manuals for full details.