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  Daylight Applet / Tageslicht-Applet

The graphic lines for sunrise, sunset and twilight times don't take into account daylight saving time.
During Daylight Savings the lines shift up by 1 hour, except for the Sun position marker.

Registration

Location:	Select your location from the menu list, enter Latitude and Longitude manually (decimal degree values and press return key), or simply click into the word map.
Look up your coordinates:	in the location database (Heavens Above): 2 million towns and villages world-wide, or in my small database here Enter latitude in decimal degrees and press return key,   enter longitude in decimal degrees and press return key.
Time Zone	Find the time zone (and Coordinates) of cities worldwide: The World Clock Interactive time zone map of countries around the world.
Key commands:	you may use the keys "h", "d", "m" to increase the hour, date, or month, or Shift key and "h", "d", "m" to decrease the hour, date, or month ! Click the applet first !
	you may enter your home location and change the horizon view image
All data	can be written to a data window
	Select from the menu to see the horizon at the selected location and time, or the word map showing day and night regions, or the sunshine hours per month.

Compare: Night Hours Applet

Compare: Solstice Daylight Applet

Select "Month" or "Year" from the "Write..." menu to open the data window
showing sunrise, sunset and twilight times:

Select "Summary Year" from the "Write..." menu:

The longest day (sommer solstice) is not the day of earliest surise and/or latest sunset,
the shortest day (winter solstice) is not the day of latest surise and/or earliest sunset !

Select "Seasons" from the "Write..." menu:

Daylight hours 2005 Berlin (52.51° N):
mean of 12.29 hours per day, total 4485.56 hours.

Daily difference of daylight 2005 Berlin (52.51° N):
near the equinoxes the absulute difference is a maximum (4 minutes).

Select "Duration of Sunlight" from the "View" menu (calculating for 1 or 2 minutes):
Duration of Sunlight depending on the Date and the Latitude
Computed using the diurnal arc of the Sun (arc described by the Sun while above the horizon):
α = arcos((cos(z)-sin(latitude)*sin(declination)/(cos(latitude)*cos(declination))
z=distance from the zenith (90.833° at rise/set)
duration of daylight: T=2*(α/360°)*24h

Difference of daylight per week 2005 Berlin (52.51° N):
near the equinoxes the absulute difference is a maximum (30 minutes).

Due to the excentricity of the Earth's path, the percentage of daylight hours over a year is greater than 50 % for all latitudes ! (semidiameter of the Sun and atmospheric refraction taken into account).
	The latest sunrise and the earliest sunset do not occur on the day of winter solstice. The dates are different and depend on the geographical latitude.   The sunrise/sunset diagram is for Berlin (52.51° N, 13.41° E): Latest sunrise (2002): December 30 at 07:17.1 UT. Earliest sunset (2002): December 14 at 14:52.2 UT. For higher northern latitudes the date of latest sunrise will be earlier, and the date of earliest sunset will be later.
	Shortest day: December 21, 7 hours 39 minutes 27 sec.
	Longest day 2004: June 21: 16.843 hours.
	Earliest sunrise 2004: June 17 at 3:43 CET
	Latest sunset 2004: June 24 at 20:43 CET.

twilight (horizon view)			civil twilight: 0 < altitude < - 6º nautical twilight: - 6º < altitude < - 12º astronomical twilight: - 12º < altitude < - 18º
twilight diagram Twilight: dark astr. naut. civil day-light
Twilight duration at 0° N (minutes before rise):         Twilight duration at 30° N (minutes before rise):       Twilight duration at 60° N (minutes before rise):		civil naut. astron. Mar 21 21 45 69 Jun 21 23 49 75 Sep 23 21 45 69 Dec 21 23 49 75 civil naut. astron. Mar 21 24 52 80 Jun 21 28 61 97 Sep 23 24 52 80 Dec 21 27 56 86 civil naut. astron. Mar 21 42 92 146 Jun 21 107 - - Sep 23 42 92 146 Dec 21 58 115 166
elevation and azimuth		the elevation (above horizon) and azimuth angle of the sun and it's direction (in brackets) 0º = N, 90º = E 180º = S, 270º = W
user input / latitude, longitude:		enter latitude, and press return key (not enter key !)	- degrees latitude as a non-negative integer or decimal (0° to 90º), and select "N" or "S"
	.	enter longitude, and press return key	- degrees longitude as a non negative integer or decimal (0º to 180º), and select "E" or "W"
	Look up your coordinates:  location database of DLR (Deutsches Zentrum für Luft- und Raumfahrt): 2 million towns and villages world-wide !
		The coordinates of the user location are stored (during applet lifetime) and can be recalled by the location menu item "User Input".
home location	Change the parameter values of "location", "latitude" and "longitude" parameters: enter southern latitude and western longitudes with minus sign !	<APPLET CODE="daylightxxx.class" archive="Applet/JavaClasses.jar" NAME="Daylight" WIDTH=600 HEIGHT=490 ALIGN=bottom> <PARAM name="email" value="replace"> <PARAM name="password" value="12345"> <PARAM NAME=location VALUE=Berlin> <PARAM NAME=latitude VALUE="52.51"> <PARAM NAME=longitude VALUE="13.41"> <PARAM NAME=server VALUE="0"> </APPLET>
Time Zone Offset		time difference between zone time and Greenwich Time (GMT ) e.g. -5 h is the value computed from the longitude, which may differ from the actual time zone offset. If necessary, select the correct time zone offset from the menu.	Central European Daylight Time = GMT + 2 hours Central European Time = GMT + 1 hour "time zone offset is +2 h" (for Central European Daylight Time) If necessary, select the correct time zone offset from the menu.
declination and GHA		the declination and Greenwich-Hour-Angle (GHA) are the coordinates (latitude and longitude) of the sun's Geographical Position (GP), where the line from the sun to the centre of the earth intersects it's surface.
equation of time		The Equation of time is the difference between the time determined by a sundial and the clock time. It is due to the obliquity and the unequal motion of the sun (ellipse).	For detailed information: Royal Greenwich Observatory Information 'The Equation of Time'
daylight hours		The total of daylight hours per month and per year is written to the diagram.

Web Links

Why the earliest sunset, latest sunrise, and shortest day of the year occur on different dates (by John Holtz) Why aren't the earliest sunset and latest sunrise on the same day as the winter solstice? (Larry Denenberg) Length of Day (Herbert Glarner) Comparative Lengths of Days and Nights Frühester Sonnenuntergang, kürzester Tag, spätester Sonnenaufgang - ein Rätsel?

Last Modified: 2010, Jan 02