You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
45 lines
1.1 KiB
45 lines
1.1 KiB
<sect1 id="ai-zenith">
|
|
<sect1info>
|
|
<author
|
|
><firstname
|
|
>Jason</firstname
|
|
> <surname
|
|
>Harris</surname
|
|
> </author>
|
|
</sect1info>
|
|
<title
|
|
>The Zenith</title>
|
|
<indexterm
|
|
><primary
|
|
>Zenith</primary>
|
|
<seealso
|
|
>Horizontal Coordinates</seealso>
|
|
</indexterm>
|
|
<para
|
|
>The Zenith is the point in the sky where you are looking when you look <quote
|
|
>straight up</quote
|
|
> from the ground. More precisely, it is the point on the sky with an <firstterm
|
|
>Altitude</firstterm
|
|
> of +90 Degrees; it is the Pole of the <link linkend="horizontal"
|
|
>Horizontal Coordinate System</link
|
|
>. Geometrically, it is the point on the <link linkend="ai-csphere"
|
|
>Celestial Sphere</link
|
|
> intersected by a line drawn from the centre of the Earth through your location on the Earth's surface. </para
|
|
><para
|
|
>The Zenith is, by definition, a point along the <link linkend="ai-meridian"
|
|
>Local Meridian</link
|
|
>. </para>
|
|
<tip>
|
|
<para
|
|
>Exercise:</para>
|
|
<para
|
|
>You can point to the Zenith by pressing <keycap
|
|
>Z</keycap
|
|
> or by selecting <guimenuitem
|
|
>Zenith</guimenuitem
|
|
> from the <guimenu
|
|
>Location</guimenu
|
|
> menu. </para>
|
|
</tip>
|
|
</sect1>
|