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DateTime::Format::EpocUserDContributed Perl DocuDateTime::Format::Epoch::JD(3)

NAME
       DateTime::Format::Epoch::JD - Convert DateTimes to/from Julian Days

SYNOPSIS
	 use DateTime::Format::Epoch::JD;

	 my $dt	= DateTime::Format::Epoch::JD->parse_datetime( 2453244.5 );
	  # 2004-08-27T00:00:00
	 DateTime::Format::Epoch::JD->format_datetime($dt);
	  # 2453244.5

	 my $formatter = DateTime::Format::Epoch::JD->new();
	 my $dt2 = $formatter->parse_datetime( 2453244.5 );
	  # 2004-08-27T00:00:00
	 $formatter->format_datetime($dt2);
	  # 2453244.5

DESCRIPTION
       This module can convert a DateTime object (or any object	that can be
       converted to a DateTime object) to the Julian Day number. This is the
       number of days since noon U.T.C.	on January 1, 4713 B.C.	(Julian
       calendar).

       This time scale was originally proposed by John Herschel, and is	often
       used in astronomical calculations.

       Similar modules are:

       o   DateTime::Format::Epoch::MJD

	   Implements the "modified Julian Day", starting at midnight U.T.C.,
	   November 17,	1858.  This number is always 2,400,000.5 lower than
	   the JD, and this count only uses five digits	to specify a date
	   between 1859	and about 2130.

       o   DateTime::Format::Epoch::RJD

	   Implements the "reduced Julian Day",	starting at noon U.T.C.,
	   November 16,	1858.  This number is always 2,400,000 lower than the
	   JD.

       o   DateTime::Format::Epoch::TJD

	   Implements the "truncated Julian Day", starting at midnight U.T.C.,
	   May 24, 1968.  This number is always	2,440,000,5 lower than the JD.
	   Actually, there is another version of the TJD, defined as JD	modulo
	   10,000.  But	that one is a bit harder to implement, so you'll have
	   to do with this version of TJD.  Or don't use TJD's at all.

       o   DateTime::Format::Epoch::RataDie

	   Implements the Rata Die count, starting at January 1, 1
	   (Gregorian).	 This count is used by DateTime::Calendar programmers.

       o   DateTime::Format::Epoch::Lilian

	   Implements the Lilian count,	named after Aloysius Lilian (a 16th
	   century physician) and first	used by	IBM (a 19th century punched
	   card	machine	manufacturer).	This counts the	number of days since
	   the adoption	of the Gregorian calendar.  Only days are counted, and
	   October 15, 1584 is day 1.

METHODS
       Most of the methods are the same	as those in DateTime::Format::Epoch.
       The only	difference is the constructor.

       o   new()

	   Constructor of the formatter/parser object. It has no parameters.

SUPPORT
       Support for this	module is provided via the datetime@perl.org email
       list. See http://lists.perl.org/	for more details.

AUTHOR
       Eugene van der Pijll <pijll@gmx.net>

COPYRIGHT
       Copyright (c) 2004 Eugene van der Pijll.	 All rights reserved.  This
       program is free software; you can redistribute it and/or	modify it
       under the same terms as Perl itself.

SEE ALSO
       DateTime

       datetime@perl.org mailing list

perl v5.32.1			  2010-08-24	DateTime::Format::Epoch::JD(3)

NAME | SYNOPSIS | DESCRIPTION | METHODS | SUPPORT | AUTHOR | COPYRIGHT | SEE ALSO

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