$c = new Astro::Coords::Equatorial(
                          name =>
                          ra =>
                          dec =>
                          long =>
                          lat =>
                          pm =>
                          parallax =>
                          type =>
                          units =>
                          epoch =>
                         );
    

"ra" and "dec" are used for HMSDeg systems (eg type=J2000). Long and Lat are used for degdeg systems (eg where type=galactic). "type" can be "galactic", "j2000", "b1950", and "supergalactic". The "units" can be specified as "sexagesimal" (when using colon or space-separated strings), "degrees" or "radians". The default is determined from context. A reference to a 2-element array can be given to specify different units for the two coordinates, e.g. "['hours', 'degrees']".

The name is just a string you can associate with the sky position.

All coordinates are converted to FK5 J2000 [epoch 2000.0] internally.

Units of parallax are arcsec. Units of proper motion are arcsec/year (no correction for declination; tropical year for B1950, Julian year for J2000). If proper motions are supplied they must both be supplied in a reference to an array:

  pm => [ 0.13, 0.45 ],
    

Additionally if non-zero proper motions are supplied then a non-zero parallax must also be supplied.

If parallax and proper motions are given, the ra/dec coordinates are assumed to be correct for the specified EQUINOX (Epoch = 2000.0 for J2000, epoch = 1950.0 for B1950) unless an explicit epoch is specified. If the epoch is supplied it is assumed to be a Besselian epoch for FK4 coordinates and Julian epoch for all others.

Radial velocities can be specified using hash arguments:

  rv  =>  radial velocity (km/s)
  vdefn => velocity definition (RADIO, OPTICAL, RELATIVSTIC) [default: OPTICAL]
  vframe => velocity reference frame (HEL,GEO,TOP,LSRK,LSRD) [default: HEL]
    

Note that the radial velocity is only used to calculate position if parallax or proper motions are also supplied. These values will be used for calculating a doppler correction.

Additionally, a redshift can be specified:

  redshift => 2.3
    

this overrides rv, vdefn and vframe. A redshift is assumed to be an optical velocity in the heliocentric frame.

Usually called via "Astro::Coords" as a factor method.

  ($ra, $dec) = $c->radec();
    

For J2000 coordinates without proper motions or parallax, this will return the same values as returned from the "radec2000" method.

An explicit equinox can be supplied as either Besselian or Julian epoch:

  ($ra, $dec) = $c->radec( 'B1950' );
  ($ra, $dec) = $c->radec( 'J2050' );
  ($ra, $dec) = $c->radec( 'B1900' );
    

Defaults to 'J2000'. Note that the epoch (as stored in the "datetime" attribute) is required when converting from FK5 to FK4 so calling this method with 'B1950' will not be the same as calling the "radec1950" method unless the "datetime" epoch is B1950.

Coordinates are returned as two "Astro::Coords::Angle" objects.

  $ra = $c->ra( format => 's' );
    

For J2000 coordinates without proper motions or parallax, this will return the same values as returned from the "ra2000" method.

See "NOTES" in Astro::Coords for details on the supported format specifiers and default calling convention.

  $dec = $c->dec( format => 's' );
    

For J2000 coordinates without proper motions or parallax, this will return the same values as returned from the "dec2000" method.

See "NOTES" in Astro::Coords for details on the supported format specifiers and default calling convention.

Proper motions and parallax are taken into account (although this may happen in the object constructor). Use the "radec" method if you want J2000, reference epoch.

  ($ra, $dec) = $c->radec2000;
    

Results are returned as "Astro::Coords::Angle" objects.

Proper motions and parallax are taken into account (although this may happen in the object constructor). Use the "ra" method if you want J2000, reference epoch.

  $ra = $c->ra2000( format => "s" );
    

See "NOTES" in Astro::Coords for details on the supported format specifiers and default calling convention.

  $dec = $c->dec( format => "sexagesimal" );
    

Proper motions and parallax are taken into account (although this may happen in the object constructor). Use the "dec" method if you want J2000, reference epoch.

See "NOTES" in Astro::Coords for details on the supported format specifiers and default calling convention.

  $par = $c->parallax();
  $c->parallax( 0.13 );
    

  @pm = $self->pm();
  $self->pm( $pm1, $pm2);
    

If the proper motions are not defined, an empty list will be returned.

If non-zero proper motions are supplied then a non-zero parallax must also be supplied.

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

This method returns a standardised set of elements across all types of coordinates.

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

Returns RA and Dec (J2000) in string format.

  $summary = $c->summary();
    

  $c->set_vel_pars( $rv, $vdefn, $vframe );
    

This does not include redshift.