yellow circle is the image point of the sun, where the line from the
sun to the center of the earth intersects it's surface. The
coordinates (latitude and longitude) are the same as the declination
and Greenwich-Hour-Angle (GHA) of the sun.
click into the map dispays the coordinates, the shadow of a 50 pixel
vertical gnomon, and the elevation of the sun.
applet should display the correct time difference between zone time
and Greenwich Time (GMT ):