This used to be just the code from wmSun warmed over and stuffed into
the gkrellmoon plugin. Now it's got a bit more original stuff in it.
But it's also got a bit more of gkrellmoon, too. So it's still mostly
from somewhere else.

The gkrellsun plugin displays the sunrise and sunset times for the
specified latitude and longitude in the current timezone. It also
displays a graph showing the trajectory of the sun across the sky (at
both the current latitude and longitude and as it would appear if it
went directly overhead at solar noon). Finally, it displays a little
rising and setting moon.

The suninfo program prints the sunrise and sunset times on stdout.
If you use the -v option, it prints a bunch of other stuff, too.

The gkrellsun plugin now has several options:

* Use 24 hour clock

  Display times of day in 24 hour style instead of am/pm style

* Show moon

  If this option is enabled, the rising and setting moon is displayed.

* Show star

  This option controls the display of a little sun icon on the panel.
  If show star is enabled, a small "star" will be drawn on top of the
  display. The star will progress from left to right across the
  display as the day passes. Its height is calculated according to the
  suns relative altitude in the sky. On a day when (and at a position
  where) the sun will be directly overhead at solar noon, this star
  will follow a semi-circular course passing through the center of the
  display. On all other days, it'll follow a "flattened" circle across
  the display.

* Show path

  If this option is enabled, a dotted line is added to the display
  showing the arc that the star follows across the display.

* Show apogee path

  If this option is enabled, a dotted line is added to the display
  showing the "apogee sun" arc. That is, the path that would be
  followed if the sun were to pass directly overhead at solar noon.

* Use orange sun

  This option enables an alternate solar image. This option also
  controls the style of numerals used to show sunrise and sunset
  times.

  This image varies in intensity over the course of the day and
  is "black" at night.

  When this option is used, sunrise and sunset times are displayed
  in the upper left and right corners of the panel, respectively.

* Show sun rise/set ETA

  If this option is enabled (and you use the orange sun), the
  estimated time of arrival of sunrise will be shown before the sun
  rises and the ETA of the sunset will be shown after the sun has
  risen.