NAME
    Astro::Sunrise - Perl extension for computing the sunrise/sunset on a given day

SYNOPSIS
      use Astro::Sunrise;
      
      ($sunrise, $sunset) = sunrise(YYYY,MM,DD,longitude,latitude,Time Zone,DST);

DESCRIPTION
  
   This module will return the sunrise/sunset for a given day. 
   
   Eastern longitude is entered as a positive number
   Western longitude is entered as a negative number
   Northern latitude is entered as a positive number
   Southern latitude is entered as a negative number
       There are a number of altitides to chose from, I have chosen
       -0.833 because this is what most countries use. Feel free to 
       change it if you need to. Here is the list:
       h = 0 degrees: Center of Sun's disk touches a mathematical horizon
       h = -0.25 degrees: Sun's upper limb touches a mathematical horizon
       h = -0.583 degrees: Center of Sun's disk touches the horizon; atmospheric refraction accounted for
       h = -0.833 degrees: Sun's supper limb touches the horizon; atmospheric refraction accounted for
       h = -6 degrees: Civil twilight (one can no longer read outside without artificial illumination)
       h = -12 degrees: Nautical twilight (navigation using a sea horizon no longer possible)
       h = -15 degrees: Amateur astronomical twilight (the sky is dark enough for most astronomical observations)
       h = -18 degrees: Astronomical twilight (the sky is completely dark)

  sunrise

        ($sunrise, $sunset) = sunrise(YYYY,MM,DD,longitude,latitude,Time Zone,DST);
        ($sunrise, $sunset) = sunrise( 2001, 3, 10, 17.384, 98.625, -5, 0 );

    Returns the sunrise and sunset times, in HH:MM format. (Note: Time Zone is the offset from GMT and DST is daylight
    savings time, 1 means DST is in effect and 0 is not.

AUTHOR
    Ron Hill rkhill@pacbell.net

    Many thanks also go to Paul Schlyer, Stockholm, Sweden for his excellent web page on the subject.

CREDITS
    Thanks very much to:

    Rich Bowen (rbowen@rbowen.com)
    for suggestions

COPYRIGHT and LICENSE
    Here is the copyright information provided by Paul Schlyer:

    Written as DAYLEN.C, 1989-08-16

    Modified to SUNRISET.C, 1992-12-01

    (c) Paul Schlyter, 1989, 1992

    Released to the public domain by Paul Schlyter, December 1992

    Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
    documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
    rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit
    persons to whom the Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
    Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
    WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE
    LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
    OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

SEE ALSO
    perl(1).