Home

Site Map

Search

astronomy,software,java
                      applet,shareware,sun,earth,applet
GeoAstro
Applets

Astronomy
astronomy,software,java
                    applet,shareware,sun,earth,applet
Chaos Game
astronomy,software,java
                      applet,shareware,sun,earth,applet
Java
astronomy,software,java
                    applet,shareware,sun,earth,applet
Miscel-

laneous

  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:

 latitude longitude

 

in the location database (Heavens Above): 2 million towns and villages world-wide, or in my small database here

Select latitude (northern positive, southern negative),
and longitude (eastern positive, western negative)
from the menus.
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:

daylight
          calculator

 


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

latest earliest
          rise set longest shortest day

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:

seasons spring
          summer autumn winter solstice equinox


sunshine hours

daylight hours per day

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


increase decrease daylight

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

duration of daylight and rate of change
Select "Draw Daylight" from the "Write/Draw" menu


duration of
          sunlight daylight latitude

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

increase decrease daylight

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


Select "Sunrise/Lat." from the "Write/Draw" menu:


Sunrise
              sunset latitude



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.


Look for details and explanations:

 
How to get this applet

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: 2023, Oct 04