<sect2 id="calc-dayduration"> <title>Day Duration module</title> <indexterm><primary>Tools</primary> <secondary>Astrocalculator</secondary> <tertiary>Day Duration module</tertiary> </indexterm> <screenshot> <screeninfo> The Day Duration calculator module </screeninfo> <mediaobject> <imageobject> <imagedata fileref="calc-daylength.png" format="PNG"/> </imageobject> <textobject> <phrase>Day Duration</phrase> </textobject> </mediaobject> </screenshot> <para> This module computes the length of day as well as sunrise, sun-transit (noon), and sunset times for any calendar date, for any location on Earth. First fill in the desired geographic coordinates and date, then press the <guibutton>Compute</guibutton> button. </para> </sect2>