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- FK5

# FK5

class astropy.coordinates.FK5(*args, copy=True, representation_type=None, differential_type=None, **kwargs)

  Bases: `BaseRADecFrame`

  A coordinate or frame in the FK5 system.

  Note that this is a barycentric version of FK5 - that is, the origin for this frame is the Solar System Barycenter, not the Earth geocenter.

  The frame attributes are listed under Other Parameters.

  Parameters:
    data `BaseRepresentation` subclass instance

      A representation object or `None` to have no data (or use the coordinate component arguments, see below).

    ra `Angle`, optional, keyword-only

      The RA for this object (`dec` must also be given and `representation` must be None).

    dec `Angle`, optional, keyword-only

      The Declination for this object (`ra` must also be given and `representation` must be None).

    distance `Quantity` [:ref: ‘length’], optional, keyword-only

      The Distance for this object along the line-of-sight. (`representation` must be None).

    pm_ra_cosdec `Quantity` [:ref: ‘angular speed’], optional, keyword-only

      The proper motion in Right Ascension (including the `cos(dec)` factor) for this object (`pm_dec` must also be given).

    pm_dec `Quantity` [:ref: ‘angular speed’], optional, keyword-only

      The proper motion in Declination for this object (`pm_ra_cosdec` must also be given).

    radial_velocity `Quantity` [:ref: ‘speed’], optional, keyword-only

      The radial velocity of this object.

    representation_type `BaseRepresentation` subclass, `python:str`, optional

      A representation class or string name of a representation class. This sets the expected input representation class, thereby changing the expected keyword arguments for the data passed in. For example, passing `representation_type='cartesian'` will make the classes expect position data with cartesian names, i.e. `x, y, z` in most cases unless overridden via `frame_specific_representation_info`. To see this frame’s names, check out `<this frame>().representation_info`.

    differential_type `BaseDifferential` subclass, `python:str`, `python:dict`, optional

      A differential class or dictionary of differential classes (currently only a velocity differential with key ‘s’ is supported). This sets the expected input differential class, thereby changing the expected keyword arguments of the data passed in. For example, passing `differential_type='cartesian'` will make the classes expect velocity data with the argument names `v_x, v_y, v_z` unless overridden via `frame_specific_representation_info`. To see this frame’s names, check out `<this frame>().representation_info`.

    copy bool, optional

      If `True` (default), make copies of the input coordinate arrays. Can only be passed in as a keyword argument.

  Other Parameters:
    equinox `Time`

      The equinox of this frame.

  Attributes Summary

  `default_differential` | Default representation for differential data (e.g., velocity)
  `default_representation` | Default representation for position data
  `equinox` |
  `frame_attributes` |
  `frame_specific_representation_info` | Mapping for frame-specific component names
  `name` |

  Attributes Documentation

  default_differential

    Default representation for differential data (e.g., velocity)

  default_representation

    Default representation for position data

  equinox = <Time object: scale='tt' format='jyear_str' value=J2000.000>
  frame_attributes = {'equinox': <astropy.coordinates.attributes.TimeAttribute object>}
  frame_specific_representation_info

    Mapping for frame-specific component names

  name = 'fk5'