<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>