class sunpy.coordinates.frames.Heliocentric(*args, copy=True, representation_type=None, differential_type=None, **kwargs)[source] [edit on github]

Bases: astropy.coordinates.BaseCoordinateFrame

A coordinate or frame in the Heliocentric system.

  • The origin is the centre of the Sun
  • The z-axis points from the centre of the Sun to the observer.
  • The y-axis is perpendicular to the z-axis, and lies in the plane that contains the z-axis and the solar rotation axis, pointing towards the Sun’s north pole.

This frame may either be specified in Cartesian or cylindrical representation. Cylindrical representation replaces (x, y) with (rho, psi) where rho is the impact parameter and psi is the position angle in degrees.

  • representation (BaseRepresentation or None.) – A representation object. If specified, other parameters must be in keyword form and if x, y and z are specified, it must be None.
  • x (Quantity object.) – X-axis coordinate, optional, must be keyword.
  • y (Quantity object.) – Y-axis coordinate, optional, must be keyword.
  • z (Quantity object. Shared by both representations.) – Z-axis coordinate, optional, must be keyword.
  • observer (HeliographicStonyhurst, optional) – The coordinate of the observer in the solar system. Defaults to the Earth.
  • obstime (SunPy Time) – The date and time of the observation, used to convert to heliographic carrington coordinates.


>>> from astropy.coordinates import SkyCoord, CartesianRepresentation
>>> import sunpy.coordinates
>>> import astropy.units as u
>>> sc = SkyCoord(CartesianRepresentation(10*u.km, 1*u.km, 2*u.km),
...               obstime="2011/01/05T00:00:50", frame="heliocentric")
>>> sc
<SkyCoord (Heliocentric: obstime=2011-01-05 00:00:50, observer=<HeliographicStonyhurst Coordinate (obstime=2011-01-05 00:00:50): (lon, lat, radius) in (deg, deg, AU)
    (0., -3.43939103, 0.98334411)>): (x, y, z) in km
    (10., 1., 2.)>
>>> sc = SkyCoord([1,2]*u.km, [3,4]*u.m, [5,6]*u.cm, frame="heliocentric", obstime="2011/01/01T00:00:54")
>>> sc
<SkyCoord (Heliocentric: obstime=2011-01-01 00:00:54, observer=<HeliographicStonyhurst Coordinate (obstime=2011-01-01 00:00:54): (lon, lat, radius) in (deg, deg, AU)
    (0., -2.97725356, 0.98335586)>): (x, y, z) in (km, m, cm)
    [(1., 3., 5.), (2., 4., 6.)]>

Attributes Summary


Attributes Documentation

frame_attributes = OrderedDict([('obstime', <sunpy.coordinates.frameattributes.TimeFrameAttributeSunPy object>), ('observer', <sunpy.coordinates.frameattributes.ObserverCoordinateAttribute object>)])
name = 'heliocentric'
observer = 'earth'
obstime = None