<sect2 id="calc-sidereal">
<title>Sidereal Time module</title>
<indexterm><primary>Tools</primary>
<secondary>Astrocalculator</secondary>
<tertiary>Sidereal Time module</tertiary>
</indexterm>

<screenshot>
<screeninfo>
The Sidereal Time calculator module
</screeninfo>
<mediaobject>
  <imageobject>
    <imagedata fileref="calc-sidereal.png" format="PNG"/>
  </imageobject>
  <textobject>
    <phrase>Sidereal Time</phrase>
  </textobject>
</mediaobject>
</screenshot>

<para>
This module converts between <link linkend="ai-utime">Universal 
Time</link> and Local <link linkend="ai-sidereal">Sidereal Time</link>.
First, select whether you will use Universal Time or Sidereal Time
as an input value in the <guilabel>Input Selection</guilabel> section.
You must also specify a geographic longitude, and a date for the 
calculation, in addition to either the Universal Time or the Sidereal 
Time value.  When you press the <guibutton>Compute</guibutton> button, 
the corresponding value for the other Time will be displayed.
</para>
</sect2>