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MoonPhase.pm  view on Meta::CPAN

	} while (abs($delta) > $EPSILON);
	return ($e);
}



# phase - calculate phase of moon as a fraction:
#
# The argument is the time for which the phase is requested,
# expressed as a Julian date and fraction.  Returns the terminator
# phase angle as a percentage of a full circle (i.e., 0 to 1),
# and stores into pointer arguments the illuminated fraction of
# the Moon's disc, the Moon's age in days and fraction, the
# distance of the Moon from the centre of the Earth, and the
# angular diameter subtended by the Moon as seen by an observer
# at the centre of the Earth.

sub phase {
	my $pdate = jtime(shift || time());

	my $pphase;				# illuminated fraction

MoonPhase.pm  view on Meta::CPAN

	  $SunDist,
	  $SunAng )  = phase($seconds_since_1970);

	  $MoonPhase = phase($seconds_since_1970);

The argument is the time for which the phase is requested,
expressed as a time returned by the C<time> function. If C<$seconds_since_1970>
is omitted, it does C<phase(time)>.

Return value in scalar context is $MoonPhase,
the terminator phase angle as a percentage of a full circle (i.e., 0 to 1).

=over 4

=item B<Return values in array context:>

=item $MoonPhase:

the terminator phase angle as a percentage of a full circle (i.e., 0 to 1)

=item $MoonIllum:

the illuminated fraction of the Moon's disc

=item $MoonAge:

the Moon's age in days and fraction

=item $MoonDist: