NAME
    Time::JulianDay -- Julian calendar manipulations

SYNOPSIS
            use Time::JulianDay

            $jd = julian_day($year, $month_1_to_12, $day)
            $jd = local_julian_day($seconds_since_1970);
            $jd = gm_julian_day($seconds_since_1970);
            ($year, $month_1_to_12, $day) = inverse_julian_day($jd)
            $dow = day_of_week($jd) 

            print (Sun,Mon,Tue,Wed,Thu,Fri,Sat)[$dow];

            $seconds_since_jan_1_1970 = jd_secondslocal($jd, $hour, $min, $sec)
            $seconds_since_jan_1_1970 = jd_secondsgm($jd, $hour, $min, $sec)
            $seconds_since_jan_1_1970 = jd_timelocal($sec,$min,$hours,$mday,$month_0_to_11,$year)
            $seconds_since_jan_1_1970 = jd_timegm($sec,$min,$hours,$mday,$month_0_to_11,$year)

DESCRIPTION
    JulianDay is a package that manipulates dates as number of days since
    some time a long time ago. It's easy to add and subtract time using
    julian days...

    The day_of_week returned by day_of_week() is 0 for Sunday, and 6 for
    Saturday and everything else is in between.

ERRATA
    Time::JulianDay is not a correct implementation. There are two problems.
    The first problem is that Time::JulianDay only works with integers.
    Julian Day can be fractional to represent time within a day. If you call
    inverse_julian_day() with a non-integer time, it will often give you an
    incorrect result.

    The second problem is that Julian Days start at noon rather than
    midnight. The julian_day() function returns results that are too large
    by 0.5.

    What to do about these problems is currently open for debate. I'm
    tempted to leave the current functions alone and add a second set with
    more accurate behavior.

    There is another implementation in Astro::Time that may be more
    accurate.

GENESIS
    Written by David Muir Sharnoff <cpan@dave.sharnoff.org> with help from
    previous work by Kurt Jaeger aka PI
    <zrzr0111@helpdesk.rus.uni-stuttgart.de> based on postings from: Ian
    Miller <ian_m@cix.compulink.co.uk>; Gary Puckering
    <garyp%cognos.uucp@uunet.uu.net> based on Collected Algorithms of the
    ACM ?; and the unknown-to-me author of Time::Local.

LICENSE
    Copyright (C) 1996-1999 David Muir Sharnoff. License hereby granted for
    anyone to use, modify or redistribute this module at their own risk.
    Please feed useful changes back to cpan@dave.sharnoff.org.