Select a location from the City
pulldown menu, or select "Enter Lat/Long ->" from
the pulldown menu, and manually enter the latitude, longitude
and time zone information in the appropriate text boxes.
The following sign conventions are used:
Longitude:
Latitude:
Positive in Western
Hemisphere
Positive in Northern
Hemisphere
Negative in Eastern
Hemisphere
Negative in Southern
Hemisphere
Latitude and Longitude can be in deg/min/sec, or decimal degrees entered
in the "Deg:" field. If you select a city from the pulldown menu,
the latitude, longitude and time zone fields will be filled in automatically.
If you want to input latitude, longitude or time zone manually, be
sure to select "Enter Lat/Long -->" from the City pulldown box,
or your numbers will be overwritten by the selected city's
location.
You can enter a different time zone for a location
by selecting "Enter Lat/Long -->" in the City pulldown
box. Otherwise, the time zone associated with the selected
city's Local Standard Time will be automatically entered.
Selecting "Yes" in the Daylight Saving field will cause the
resulting sunrise, sunset and solar noon times to be adjusted
forward one hour. If you are uncertain of the time zone for
a location, refer to the NOAA Time
Zone Table.
The program retrieves the current date from
your computer, and fills the month, day and year fields.
To perform calculations for a different date, simply select
a month in the pull down menu, and enter the day and four
digit year in the appropriate input boxes. When entering
a day or year, you will need to click the "Calculate Sunrise/Sunset" button
to update the results for this date.
Once the calculation results are displayed,
you may use your web browser's "Print" function to obtain
a hardcopy of the results.
For locations above the Arctic Circle and below
the Antarctic Circle, when a sunrise or sunset does not occur
on the given day the program locates the local time and date
of the most recent sunrise or sunset, and the next sunset
or sunrise. When this occurs, the UTC fields will display "prior" or "next" information
instead of the UTC times.
NOTE: For latitudes greater than 72 degrees
N and S, calculations are accurate to within 10 minutes.
For latitudes less than +/- 72° accuracy is approximately
one minute. See Solar
Calculation Details for further explanation.