- Compute the sunrise, sunset, and twilight times. This method
is used to compute the times displayed in the text panel. Its accuracy is
adequate for rising and setting phenomenon. Algorithms from
"Astronomy on the Personal Computer."
The hierarchical list routines were adapted from an
article in Java World, January 1997, and from
my article in Apple's develop magazine issue 18, June 1994.
Several of the utility routines were adapted from David M. Geary and Alan L.
McClellan, "Graphic Java"
You can get more information (and more accurate information) about timezones,
sunrise, and moonrise times from the
Directorate of Time
at the United States Naval Observatory.
Known bugs, misfeatures, and future improvements:
When viewed from the Southern Hemisphere, the moon is upside down. I.e.,
when the moon looks like a D in the Northern Hemisphere,
it looks like a C in the Southern Hemisphere. To fix
this requires additional trignometry and knowledge of the sun's location.
The display looks terrible on monochrome and gray-scale displays. This could easily be
fixed if Java could tell applets more about their execution environment.
These books will be useful if you are interested in astronomical