Sunrise/Sunset

Geography options control the behaviour.

• Double click on the map
• From the popup menu, pick:

• Short table calculates sunrise/sunset
• Long table adds civil/nautical/ astronomical twilight
• Graphical plot shows sunrise, sunset, and the length of daylight at desired position throughout the year.

If you pick the icon with no map active:

• Enter latitude and longitude.
• Get Long table adds civil/nautical/ astronomical twilight

Sunrise-sunset graphs

Algorithm from pages B5-B7, Almanac for computers 1989, Nautical Almanac Office, U.S. Naval Observatory. Valid for latitudes less than 65° (deteriorates near poles when sun above or below horizon longer than 24 hours) at any time in the latter half of the 20th century. Accurate ± 2 min.

Note that these times give a best guess estimate for the difference to UTC.

Last revision 4/12/2019