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lib/Astro/Coords/Planet.pm  view on Meta::CPAN

=cut

sub array {
  my $self = shift;
  return ($self->planet, undef, undef,
          undef, undef, undef, undef, undef, undef, undef, undef);
}

=item B<type>

Returns the generic type associated with the coordinate system.
For this class the answer is always "RADEC".

This is used to aid construction of summary tables when using
mixed coordinates.

It could be done using isa relationships.

=cut

sub type {
  return "PLANET";
}

=item B<stringify>

Stringify overload. Simple returns the name of the planet
in capitals.

=cut

sub stringify {
  my $self = shift;
  return uc($self->planet());
}

=item B<summary>

Return a one line summary of the coordinates.
In the future will accept arguments to control output.

  $summary = $c->summary();

=cut

sub summary {
  my $self = shift;
  my $name = $self->name;
  $name = '' unless defined $name;
  return sprintf("%-16s  %-12s  %-13s PLANET",$name,'','');
}

=item B<diam>

Returns the apparent angular planet diameter from the most recent calculation
of the apparent RA/Dec.

 $diam = $c->diam();

Returns the answer as a C<Astro::Coords::Angle> object. Note that this
number is not updated automatically. (so don't change the time and expect
to get the correct answer without first asking for a ra/dec calculation).

=cut

sub diam {
  my $self = shift;
  if (@_) {
    my $d = shift;
    $self->{diam} = new Astro::Coords::Angle( $d, units => 'rad' );
  }
  return $self->{diam};
}

=item B<apparent>

Return the apparent RA and Dec as two C<Astro::Coords::Angle> objects for the current
coordinates and time.

 ($ra_app, $dec_app) = $self->apparent();

=cut

sub apparent {
  my $self = shift;

  my ($ra_app, $dec_app) = $self->_cache_read( "RA_APP", "DEC_APP" );

  # Need to calculate it
  if (!defined $ra_app || !defined $dec_app) {

    my $tel = $self->telescope;
    my $long = (defined $tel ? $tel->long : 0.0 );
    my $lat = (defined $tel ? $tel->lat : 0.0 );

    ($ra_app, $dec_app, my $diam) = Astro::PAL::palRdplan($self->_mjd_tt, $PLANET{$self->planet},
                                                          $long, $lat );

    # Store the diameter
    $self->diam( $diam );

    # Convert to angle objects
    $ra_app = new Astro::Coords::Angle::Hour($ra_app, units => 'rad', range => '2PI');
    $dec_app = new Astro::Coords::Angle($dec_app, units => 'rad');

    # store in cache
    $self->_cache_write( "RA_APP" => $ra_app, "DEC_APP" => $dec_app );
  }

  return ($ra_app, $dec_app);
}

=item B<rv>

Radial velocity of the planet relative to the Earth geocentre.

=cut

sub rv {
  croak "Not yet implemented planetary radial velocities";
}