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tdeedu/doc/kstars/calc-julianday.docbook

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<sect2 id="calc-julian">
<title>Julian Day module</title>
<indexterm><primary>Tools</primary>
<secondary>Astrocalculator</secondary>
<tertiary>Julian Day module</tertiary>
</indexterm>
<screenshot>
<screeninfo>
The Julian Day calculator module
</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="calc-julian.png" format="PNG"/>
</imageobject>
<textobject>
<phrase>Julian Day</phrase>
</textobject>
</mediaobject>
</screenshot>
<para>
This module converts between the calendar date, the <link
linkend="ai-julianday">Julian Day</link>, and the
<firstterm>Modified Julian Day</firstterm>. The Modified Julian Day
is simply equal to the Julian Day - 2,400,000.5.
</para><para>
To use the module, select which of the three dates will be the input,
and then fill in its value. Then press the
<guibutton>Compute</guibutton> button, and the corresponding values for
the other two date systems will be displayed.
</para>
<tip>
<para>Exercise:</para>
<para>
What calendar date does MJD = 0.0 correspond to?
</para>
</tip>
</sect2>