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lib/Astro/Sunrise.pm  view on Meta::CPAN

# time of the day..
#
#
# _RETURN
#
# Sidtime
#
sub GMST0 {
    my ($d) = @_;

    my $sidtim0 = revolution(   ( 180.0 + 356.0470 + 282.9404 )
                              + ( 0.9856002585 + 4.70935E-5 ) * $d );
    return $sidtim0;

}

#
#
# FUNCTIONAL SEQUENCE for sun_RA_dec
#
# _GIVEN

lib/Astro/Sunrise.pm  view on Meta::CPAN

    #                       Mean anomaly of the Sun
    #                       Mean longitude of perihelion
    #                         Note: Sun's mean longitude = M + w
    #                       Eccentricity of Earth's orbit
    #                       Eccentric anomaly
    #                       x, y coordinates in orbit
    #                       True anomaly

    # Compute mean elements
    my $Mean_anomaly_of_sun = revolution( 356.0470 + 0.9856002585 * $d );
    my $Mean_longitude_of_perihelion = 282.9404 + 4.70935E-5 * $d;
    my $Eccentricity_of_Earth_orbit  = 0.016709 - 1.151E-9 * $d;

    # Compute true longitude and radius vector
    my $Eccentric_anomaly =   $Mean_anomaly_of_sun
                            + $Eccentricity_of_Earth_orbit * $RADEG
                               * sind($Mean_anomaly_of_sun)
                               * ( 1.0 + $Eccentricity_of_Earth_orbit * cosd($Mean_anomaly_of_sun) );

    my $x = cosd($Eccentric_anomaly) - $Eccentricity_of_Earth_orbit;