date_sunset
    (PHP 5)
date_sunset -- 
   Returns time of sunset for a given day and location
  
Description
mixed 
date_sunset ( int timestamp [, int format [, float latitude [, float longitude [, float zenith [, float gmt_offset]]]]] )
    date_sunset() returns the sunset time for a given
    day (specified as a timestamp) and location.
   
Parameters
   
- timestamp
 
       The timestamp of the day from which the sunset
       time is taken.
      
- format
 
       
Table 1. format constants
| constant | description | example | 
|---|
| SUNFUNCS_RET_STRING | returns the result as string | 16:46 | 
| SUNFUNCS_RET_DOUBLE | returns the result as float | 16.78243132 | 
| SUNFUNCS_RET_TIMESTAMP | returns the result as integer (timestamp) | 1095034606 | 
 
      - latitude
 
       Defaults to North, pass in a negative value for South.
       See also: date.default_latitude
      
- longitude
 
       Defaults to East, pass in a negative value for West.
       See also: date.default_longitude
      
- zenith
 
       Default: date.sunrise_zenith
      
- gmtoffset
 
       Specified in hours.
      
 
  Errors/Exceptions
Every call to a date/time function will generate a E_NOTICE 
if the time zone is not valid, and/or a E_STRICT message
if using the system settings or the TZ environment
variable. See also date_default_timezone_set()
Return Values
   Returns the sunset time in a specified format on
   success, or FALSE on failure.
  
Examples
   
Example 1. date_sunset() example 
<?php
  /* calculate the sunset time for Lisbon, Portugal Latitude: 38.4 North Longitude: 9 West Zenith ~= 90 offset: +1 GMT */
  echo date("D M d Y"). ', sunset time : ' .date_sunset(time(), SUNFUNCS_RET_STRING, 38.4, -9, 90, 1);
  ?>
 |  
 The above example will output 
something similar to: Mon Dec 20 2004, sunset time : 18:13  |  
  |