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package Astro::Montenbruck::Ephemeris::Planet::Sun;
use strict;
use warnings;
use base qw/Astro::Montenbruck::Ephemeris::Planet/;
use Math::Trig qw/:pi rad2deg/;
use Astro::Montenbruck::MathUtils qw /frac ARCS reduce_rad/;
use Astro::Montenbruck::Ephemeris::Pert qw/pert/;
use Astro::Montenbruck::Ephemeris::Planet qw/$SU/;
our $VERSION = 0.01;
sub new {
    my $class = shift;
    $class->SUPER::new( id => $SU );
}
sub position {
    my ( $self, $t ) = @_;
    # mean anomalies of planets and mean arguments of lunar orbit [rad]
    my $m2 = pi2 * frac( 0.1387306 + 162.5485917 * $t );
    my $m3 = pi2 * frac( 0.9931266 + 99.9973604 * $t );
    my $m4 = pi2 * frac( 0.0543250 + 53.1666028 * $t );
    my $m5 = pi2 * frac( 0.0551750 + 8.4293972 * $t );
    my $m6 = pi2 * frac( 0.8816500 + 3.3938722 * $t );
    my $d = pi2 * frac( 0.8274 + 1236.8531 * $t );
    my $a = pi2 * frac( 0.3749 + 1325.5524 * $t );
    my $u = pi2 * frac( 0.2591 + 1342.2278 * $t );
    my ( $dl, $dr, $db ) = ( 0, 0, 0 );    # Corrections in longitude ["],
    my $pert_cb = sub { $dl += $_[0]; $dr += $_[1]; $db += $_[2] };
    # Keplerian terms and perturbations by Venus
    my $term = pert(
        T        => $t,
        M        => $m3,
        m        => $m2,
        I_min    => 0,
        I_max    => 7,
        i_min    => -6,
        i_max    => 0,
        callback => $pert_cb
    );
    $term->( 1, 0,  0, -0.22, 6892.76, -16707.37, -0.54, 0,     0 );
    $term->( 1, 0,  1, -0.06, -17.35,  42.04,     -0.15, 0.00,  0.00 );
    $term->( 1, 0,  2, -0.01, -0.05,   0.13,      -0.02, 0.00,  0.00 );
    $term->( 2, 0,  0, 0.00,  71.98,   -139.57,   0.00,  0.00,  0.00 );
    $term->( 2, 0,  1, 0.00,  -0.36,   0.70,      0.00,  0.00,  0.00 );
    $term->( 3, 0,  0, 0.00,  1.04,    -1.75,     0.00,  0.00,  0.00 );
    $term->( 0, -1, 0, 0.03,  -0.07,   -0.16,     -0.07, 0.02,  -0.02 );
    $term->( 1, -1, 0, 2.35,  -4.23,   -4.75,     -2.64, 0.00,  0.00 );
    $term->( 1, -2, 0, -0.10, 0.06,    0.12,      0.20,  0.02,  0.00 );
    $term->( 2, -1, 0, -0.06, -0.03,   0.20,      -0.01, 0.01,  -0.09 );
    $term->( 2, -2, 0, -4.70, 2.90,    8.28,      13.42, 0.01,  -0.01 );
    $term->( 3, -2, 0, 1.80,  -1.74,   -1.44,     -1.57, 0.04,  -0.06 );
    $term->( 3, -3, 0, -0.67, 0.03,    0.11,      2.43,  0.01,  0.00 );
    $term->( 4, -2, 0, 0.03,  -0.03,   0.10,      0.09,  0.01,  -0.01 );
    $term->( 4, -3, 0, 1.51,  -0.40,   -0.88,     -3.36, 0.18,  -0.10 );
    $term->( 4, -4, 0, -0.19, -0.09,   -0.38,     0.77,  0.00,  0.00 );
    $term->( 5, -3, 0, 0.76,  -0.68,   0.30,      0.37,  0.01,  0.00 );
    $term->( 5, -4, 0, -0.14, -0.04,   -0.11,     0.43,  -0.03, 0.00 );
    $term->( 5, -5, 0, -0.05, -0.07,   -0.31,     0.21,  0.00,  0.00 );
    $term->( 6, -4, 0, 0.15,  -0.04,   -0.06,     -0.21, 0.01,  0.00 );
    $term->( 6, -5, 0, -0.03, -0.03,   -0.09,     0.09,  -0.01, 0.00 );
    $term->( 6, -6, 0, 0.00,  -0.04,   -0.18,     0.02,  0.00,  0.00 );
    $term->( 7, -5, 0, -0.12, -0.03,   -0.08,     0.31,  -0.02, -0.01 );
    # perturbations by Mars
    $term = pert(
        T        => $t,
        M        => $m3,
        m        => $m4,
        I_min    => 1,
        I_max    => 5,
        i_min    => -8,
        i_max    => -1,
        callback => $pert_cb
    );
    $term->( 1, -1, 0, -0.22, 0.17,  -0.21, -0.27, 0.00, 0.00 );
    $term->( 1, -2, 0, -1.66, 0.62,  0.16,  0.28,  0.00, 0.00 );
    $term->( 2, -2, 0, 1.96,  0.57,  -1.32, 4.55,  0.00, 0.01 );
    $term->( 2, -3, 0, 0.40,  0.15,  -0.17, 0.46,  0.00, 0.00 );
    $term->( 2, -4, 0, 0.53,  0.26,  0.09,  -0.22, 0.00, 0.00 );
    $term->( 3, -3, 0, 0.05,  0.12,  -0.35, 0.15,  0.00, 0.00 );
    $term->( 3, -4, 0, -0.13, -0.48, 1.06,  -0.29, 0.01, 0.00 );
    $term->( 3, -5, 0, -0.04, -0.20, 0.20,  -0.04, 0.00, 0.00 );
    $term->( 4, -4, 0, 0.00,  -0.03, 0.10,  0.04,  0.00, 0.00 );
    $term->( 4, -5, 0, 0.05,  -0.07, 0.20,  0.14,  0.00, 0.00 );
    $term->( 4, -6, 0, -0.10, 0.11,  -0.23, -0.22, 0.00, 0.00 );
    $term->( 5, -7, 0, -0.05, 0.00,  0.01,  -0.14, 0.00, 0.00 );
    $term->( 5, -8, 0, 0.05,  0.01,  -0.02, 0.10,  0.00, 0.00 );
    # perturbations by Sun
    $term = pert(
        T        => $t,
        M        => $m3,
        m        => $m5,
        I_min    => -1,
        I_max    => 3,
        i_min    => -4,
        i_max    => -1,
        callback => $pert_cb
    );
    $term->( -1, -1, 0, 0.01,  0.07,  0.18,  -0.02,  0.00, -0.02 );
    $term->( 0,  -1, 0, -0.31, 2.58,  0.52,  0.34,   0.02, 0.00 );
    $term->( 1,  -1, 0, -7.21, -0.06, 0.13,  -16.27, 0.00, -0.02 );
    $term->( 1,  -2, 0, -0.54, -1.52, 3.09,  -1.12,  0.01, -0.17 );
    $term->( 1,  -3, 0, -0.03, -0.21, 0.38,  -0.06,  0.00, -0.02 );
    $term->( 2,  -1, 0, -0.16, 0.05,  -0.18, -0.31,  0.01, 0.00 );
    $term->( 2,  -2, 0, 0.14,  -2.73, 9.23,  0.48,   0.00, 0.00 );
    $term->( 2,  -3, 0, 0.07,  -0.55, 1.83,  0.25,   0.01, 0.00 );
    $term->( 2,  -4, 0, 0.02,  -0.08, 0.25,  0.06,   0.00, 0.00 );
    $term->( 3,  -2, 0, 0.01,  -0.07, 0.16,  0.04,   0.00, 0.00 );
    $term->( 3,  -3, 0, -0.16, -0.03, 0.08,  -0.64,  0.00, 0.00 );
    $term->( 3,  -4, 0, -0.04, -0.01, 0.03,  -0.17,  0.00, 0.00 );
    # perturbations by Saturn
    $term = pert(
        T        => $t,
        M        => $m3,
        m        => $m6,
        I_min    => -0,
        I_max    => 2,
        i_min    => -2,
        i_max    => -1,
        callback => $pert_cb
    );
    $term->( 0, -1, 0, 0.00,  0.32,  0.01,  0.00,  0.00, 0.00 );
    $term->( 1, -1, 0, -0.08, -0.41, 0.97,  -0.18, 0.00, -0.01 );
    $term->( 1, -2, 0, 0.04,  0.10,  -0.23, 0.10,  0.00, 0.00 );
    $term->( 2, -2, 0, 0.04,  0.10,  -0.35, 0.13,  0.00, 0.00 );
    # difference of Earth-Moon-barycentre and centre of the Earth
    my $dpa = $d + $a;
    my $dma = $d - $a;
    $dl +=
      +6.45 * sin($d) -
      0.42 * sin($dma) +
      0.18 * sin($dpa) +
      0.17 * sin( $d - $m3 ) -
      0.06 * sin( $d + $m3 );
    $dr +=
      +30.76 * cos($d) -
      3.06 * cos($dma) +
      0.85 * cos($dpa) -
      0.58 * cos( $d + $m3 ) +
      0.57 * cos( $d - $m3 );
    $db += +0.576 * sin($u);
    # long-periodic perturbations
    $dl +=
      +6.40 * sin( pi2 * ( 0.6983 + 0.0561 * $t ) ) +
      1.87 * sin( pi2 *  ( 0.5764 + 0.4174 * $t ) ) +
      0.27 * sin( pi2 *  ( 0.4189 + 0.3306 * $t ) ) +
      0.20 * sin( pi2 *  ( 0.3581 + 2.4814 * $t ) );
    # ecliptic coordinates ([rad],[AU])
    my $l = reduce_rad(
        pi2 * frac(
            0.7859453 + $m3 / pi2 +
              ( ( 6191.2 + 1.1 * $t ) * $t + $dl ) / 1296.0e3
        )
    );
    my $r = 1.0001398 - 0.0000007 * $t + $dr * 1.0e-6;
    my $b = $db / ARCS;
    rad2deg($l), rad2deg($b),  $r;
}
1;
__END__
HideShow 64 lines of Pod
=pod
=encoding UTF-8
=head1 NAME
Astro::Montenbruck::Ephemeris::Planet::Sun - Sun.
=head1 SYNOPSIS
  use Astro::Montenbruck::Ephemeris::Planet::Sun;
  my $planet = Astro::Montenbruck::Ephemeris::Planet::Sun->new();
  my @geo = $planet->position($t); # apparent geocentric ecliptical coordinates
=head1 DESCRIPTION
Child class of L<Astro::Montenbruck::Ephemeris::Planet>, responsible for calculating
B<Sun> position.
=head1 METHODS
=head2 Astro::Montenbruck::Ephemeris::Planet::Sun->new
Constructor.
=head2 $self->position($t)
Geocentric ecliptic coordinates of the Sun
=head3 Arguments
=over
=item B<$t> — time in Julian centuries since J2000: (JD-2451545.0)/36525.0
=back
=head3 Returns
Hash of geocentric ecliptical coordinates.
=over
=item * B<x> — geocentric longitude, arc-degrees
=item * B<y> — geocentric latitude, arc-degrees
=item * B<z> — distance from Earth, AU
=back
=head1 AUTHOR
Sergey Krushinsky, C<< <krushi at cpan.org> >>
=head1 COPYRIGHT AND LICENSE
Copyright (C) 2009-2019 by Sergey Krushinsky
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut