<sect2 id="calc-angdist"> <title>Angular Distance module</title> <indexterm><primary>Tools</primary> <secondary>Astrocalculator</secondary> <tertiary>Angular Distance module</tertiary> </indexterm> <screenshot> <screeninfo> The Angular Distance calculator module </screeninfo> <mediaobject> <imageobject> <imagedata fileref="calc-angdist.png" format="PNG"/> </imageobject> <textobject> <phrase>Angular Distance</phrase> </textobject> </mediaobject> </screenshot> <para> The Angular Distance tool is used to measure the angle between any two points on the sky. You simply specify the <link linkend="equatorial">Equatorial coordinates</link> of the desired pair of points, and then press the <guibutton>Compute</guibutton> button to obtain the angle between the two points. </para> <para> There is also a Batch mode for this module. In batch mode, you specify an input filename which contains four numbers per line: the RA and Dec values for pairs of points. Alternatively, you can specify a single value for any of these four coordinates in the calculator panel (the corresponding values in the input file should be skipped if they are specified in the calculator). </para> <para> Once you have specified the input filename and an output filename, simply press the <guibutton>Run</guibutton> button to generate the output file. </para> </sect2>