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- Astropy v5.2.1 »
- Astronomical Coordinate Systems (`astropy.coordinates`) »
- GeocentricMeanEcliptic

# GeocentricMeanEcliptic

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

  Bases: `BaseEclipticFrame`

  Geocentric mean ecliptic coordinates. These origin of the coordinates are the geocenter (Earth), with the x axis pointing to the mean (not true) equinox at the time specified by the `equinox` attribute, and the xy-plane in the plane of the ecliptic for that date.

  Be aware that the definition of “geocentric” here means that this frame includes light deflection from the sun, aberration, etc when transforming to/from e.g. ICRS.

  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).

    lon `Angle`, optional, keyword-only

      The ecliptic longitude for this object (`lat` must also be given and `representation` must be None).

    lat `Angle`, optional, keyword-only

      The ecliptic latitude for this object (`lon` must also be given and `representation` must be None).

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

      The distance for this object from the geocenter. (`representation` must be None).

    pm_lon_coslat `Quantity` [‘angualar speed’], optional, keyword-only

      The proper motion in the ecliptic longitude (including the `cos(lat)` factor) for this object (`pm_lat` must also be given).

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

      The proper motion in the ecliptic latitude for this object (`pm_lon_coslat` 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`, optional

      The date to assume for this frame. Determines the location of the x-axis and the location of the Earth (necessary for transformation to non-geocentric systems). Defaults to the ‘J2000’ equinox.

    obstime `Time`, optional

      The time at which the observation is taken. Used for determining the position of the Earth. Defaults to J2000.

  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` |
  `obstime` |

  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>, 'obstime': <astropy.coordinates.attributes.TimeAttribute object>}
  frame_specific_representation_info

    Mapping for frame-specific component names

  name = 'geocentricmeanecliptic'
  obstime = <Time object: scale='tt' format='jyear_str' value=J2000.000>