<sect2 id="calc-horiz">
<title>Horizontal Coordinates module</title>
<indexterm><primary>Tools</primary>
<secondary>Astrocalculator</secondary>
<tertiary>Horizontal Coordinates module</tertiary>
</indexterm>

<screenshot>
<screeninfo>
The Horizontal Coordinates calculator module
</screeninfo>
<mediaobject>
  <imageobject>
    <imagedata fileref="calc-horizontal.png" format="PNG"/>
  </imageobject>
  <textobject>
    <phrase>Horizontal Coordinates</phrase>
  </textobject>
</mediaobject>
</screenshot>

<para>
This module converts from <link linkend="equatorial">Equatorial 
coordinates</link> to <link linkend="horizontal">Horizontal 
coordinates</link>.  First, select the date, time, and 
geographic coordinates for the calculation in the 
<guilabel>Input Data</guilabel> section.  Then, fill in the 
equatorial coordinates to be converted and their catalog epoch 
in the <guilabel>Equatorial Coordinates</guilabel> section.
When you press the <guibutton>Compute</guibutton> button,
the corresponding Horizontal coordinates will be presented in
the <guilabel>Horizontal Coordinates</guilabel> section.
</para>
</sect2>