I added a "Day and Night World Map" to the Dawn-Dusk Times tiddler.

Just add this code:
Code:
<html><img src="http://www.timeanddate.com/scripts/sunmap.php?iso=<<today 'YYYY0MM0DDT0hh0mm'>>"></html>
It will render a map of the world with the actual day, twilight (civil, nautical and astronomical) and night areas with actual positions of Sun and Moon.

Cheers,

Jeffrey