1Time::JulianDay(3)    User Contributed Perl Documentation   Time::JulianDay(3)
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NAME

6       Time::JulianDay -- Julian calendar manipulations
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SYNOPSIS

9               use Time::JulianDay
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11               $jd = julian_day($year, $month_1_to_12, $day)
12               $jd = local_julian_day($seconds_since_1970);
13               $jd = gm_julian_day($seconds_since_1970);
14               ($year, $month_1_to_12, $day) = inverse_julian_day($jd)
15               $dow = day_of_week($jd)
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17               print (Sun,Mon,Tue,Wed,Thu,Fri,Sat)[$dow];
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19               $seconds_since_jan_1_1970 = jd_secondslocal($jd, $hour, $min, $sec)
20               $seconds_since_jan_1_1970 = jd_secondsgm($jd, $hour, $min, $sec)
21               $seconds_since_jan_1_1970 = jd_timelocal($sec,$min,$hours,$mday,$month_0_to_11,$year)
22               $seconds_since_jan_1_1970 = jd_timegm($sec,$min,$hours,$mday,$month_0_to_11,$year)
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DESCRIPTION

25       JulianDay is a package that manipulates dates as number of days since
26       some time a long time ago.  It's easy to add and subtract time using
27       julian days...
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29       The day_of_week returned by day_of_week() is 0 for Sunday, and 6 for
30       Saturday and everything else is in between.
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ERRATA

33       Time::JulianDay is not a correct implementation.  There are two
34       problems.  The first problem is that Time::JulianDay only works with
35       integers.  Julian Day can be fractional to represent time within a day.
36       If you call inverse_julian_day() with a non-integer time, it will often
37       give you an incorrect result.
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39       The second problem is that Julian Days start at noon rather than
40       midnight.  The julian_day() function returns results that are too large
41       by 0.5.
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43       What to do about these problems is currently open for debate.  I'm
44       tempted to leave the current functions alone and add a second set with
45       more accurate behavior.
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47       There is another implementation in Astro::Time that may be more
48       accurate.
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GENESIS

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

59       Copyright (C) 1996-1999 David Muir Sharnoff.  License hereby granted
60       for anyone to use, modify or redistribute this module at their own
61       risk.  Please feed useful changes back to cpan@dave.sharnoff.org.
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65perl v5.30.0                      2019-07-26                Time::JulianDay(3)
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