Sunrise Today/Sunrise Tomorrow (Hint: Run WorldClock Lite and refer to the screen while reading this documentation page from a printout.) __________________________________________________________________________ The Sunrise Today or Sunrise Tomorrow display is selected from the WorldClock Lite menu in the bar at the top of the screen. The text beneath the map indicates the times for sunrise and sunset at the computer's location. In addition, times are given for civil, nautical, and astronomical twilight. Civil twilight is bright twilight, where the sun is within 6° of the horizon. Nautical twilight is deep twilight where the sun is between 6° and 12° below the horizon. During Astronomical twilight (sun between 12° and 18° below the horizon) there is still enough light in the upper atmosphere to interfere with astronomical observations. A "Sun-Bar" near the bottom of the screen graphs the hours of day, twilight, and dark. For a quick check of sunrise, sunset, and twilight times tomorrow, choose the Sunrise Tomorrow option in the WorldClock menu. The display is the same as for Sunrise Today, except it is adjusted one day ahead. The map is an active input area on the Sunrise screens. Click on the map to see sunrise, sunset, and twilight times at any worldwide location, including near the poles. When you are done experimenting, to reset to the original setting, click the Revert button. The "Sun-Bar" is useful in this mode, giving graphical information about the length of sunrise, twilight, and nighttime around the earth. Note: When using the map for input, idealized time zones are assumed. The actual, statutory time zones are not considered in the sunrise/sunset calculations when clicking on the map as an input device.