Copy the KDE 3.5 branch to branches/trinity for new KDE 3.5 features.

BUG:215923


git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdeedu@1054174 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

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+<sect1 id="ai-cpoles">
+<sect1info>
+<author>
+<firstname>Jason</firstname>
+<surname>Harris</surname>
+</author>
+</sect1info>
+<title>The Celestial Poles</title>
+<indexterm><primary>Celestial Poles</primary>
+<seealso>Equatorial Coordinates</seealso>
+</indexterm>
+<para>
+The sky appears to drift overhead from east to west, completing a full circuit
+around the sky in 24 (<link linkend="ai-sidereal">Sidereal</link>) hours.  This
+phenomenon is due to the spinning of the Earth on its axis.  The Earth's
+spin axis intersects the <link linkend="ai-csphere">Celestial Sphere</link> at
+two points.  These points are the <firstterm>Celestial Poles</firstterm>.  As the
+Earth spins; they remain fixed in the sky, and all other points seem to rotate
+around them.  The celestial poles are also the poles of the <link
+linkend="equatorial">Equatorial Coordinate System</link>, meaning
+they have <firstterm>Declinations</firstterm> of +90 degrees and -90 degrees
+(for the North and South celestial poles, respectively).
+</para><para>
+The North Celestial Pole currently has nearly the same coordinates as
+the bright star <firstterm>Polaris</firstterm> (which is Latin for <quote>Pole Star</quote>).
+This makes Polaris useful for navigation: not only is it always above the North
+point of the horizon, but its <link
+linkend="horizontal">Altitude</link> angle is always (nearly)
+equal to the observer's <link linkend="ai-geocoords">Geographic Latitude</link>
+(however, Polaris can only be seen from locations in the Northern hemisphere).
+</para><para>
+The fact that Polaris is near the pole is purely a coincidence.  In fact,
+because of <link linkend="ai-precession">Precession</link>, Polaris is only near
+the pole for a small fraction of the time.
+</para>
+<tip>
+<para>Exercises:</para>
+<para>
+Use the <guilabel>Find Object</guilabel> window
+(<keycombo action="simul">&Ctrl;<keycap>F</keycap></keycombo>) to locate
+Polaris.  Notice that its Declination is almost (but not exactly) +90 degrees.
+Compare the Altitude reading when focused on Polaris to your location's
+geographic latitude.  They are always within one degree of each other.
+They are not exactly the same because Polaris isn't exactly at the Pole.
+(you can point exactly at the pole by switching to Equatorial
+coordinates, and pressing the up-arrow key until the sky stops scrolling).
+</para><para>
+Use the <guilabel>Time Step</guilabel> spinbox in the toolbar to accelerate time
+ to a
+step of 100 seconds.  You can see the entire sky appears to rotate around
+Polaris, while Polaris itself remains nearly stationary.
+</para><para>
+We said that the celestial pole is the pole of the Equatorial coordinate
+system.  What do you think is the pole of the horizontal (Altitude/Azimuth)
+coordinate system?  (The <link linkend="ai-zenith">Zenith</link>).
+</para>
+</tip>
+</sect1>