Helioprojective

class sunpy.coordinates.frames.Helioprojective(*args, **kwargs)[source] [edit on github]

Bases: sunpy.coordinates.frames.SunPyBaseCoordinateFrame

A coordinate or frame in the Helioprojective (Cartesian) system.

This is a projective coordinate system centered around the observer. It is a full spherical coordinate system with position given as longitude theta_x and latitude theta_y.

Parameters
  • representation (BaseRepresentation or None.) – A representation object. If specified, other parameters must be in keyword form.

  • Tx (Angle or Quantity) – X-axis coordinate.

  • Ty (Angle or Quantity) – Y-axis coordinate.

  • distance (Quantity) – The radial distance from the observer to the coordinate point.

  • obstime (SunPy Time) – The date and time of the observation, used to convert to heliographic carrington coordinates.

  • observer (HeliographicStonyhurst, str) – The coordinate of the observer in the solar system. If you supply a string, it must be a solar system body that can be parsed by get_body_heliographic_stonyhurst.

  • rsun (Quantity) – The physical (length) radius of the Sun. Used to calculate the position of the limb for calculating distance from the observer to the coordinate.

Examples

>>> from astropy.coordinates import SkyCoord
>>> import sunpy.coordinates
>>> import astropy.units as u
>>> sc = SkyCoord(0*u.deg, 0*u.deg, 5*u.km, obstime="2010/01/01T00:00:00",
...               frame="helioprojective")
>>> sc
<SkyCoord (Helioprojective: obstime=2010-01-01T00:00:00.000, rsun=695700.0 km, observer=<HeliographicStonyhurst Coordinate for 'earth'>): (Tx, Ty, distance) in (arcsec, arcsec, km)
    (0., 0., 5.)>
>>> sc = SkyCoord(0*u.deg, 0*u.deg, obstime="2010/01/01T00:00:00", frame="helioprojective")
>>> sc
<SkyCoord (Helioprojective: obstime=2010-01-01T00:00:00.000, rsun=695700.0 km, observer=<HeliographicStonyhurst Coordinate for 'earth'>): (Tx, Ty) in arcsec
    (0., 0.)>

Attributes Summary

default_differential

default_representation

frame_attributes

frame_specific_representation_info

name

observer

obstime

rsun

Methods Summary

calculate_distance()

This method calculates the third coordinate of the Helioprojective frame.

Attributes Documentation

default_differential
default_representation
frame_attributes = {'observer': <sunpy.coordinates.frameattributes.ObserverCoordinateAttribute object>, 'obstime': <sunpy.coordinates.frameattributes.TimeFrameAttributeSunPy object>, 'rsun': <astropy.coordinates.attributes.Attribute object>}
frame_specific_representation_info
name = 'helioprojective'
observer = 'earth'
obstime = None
rsun = <Quantity 695700. km>

Methods Documentation

calculate_distance()[source] [edit on github]

This method calculates the third coordinate of the Helioprojective frame. It assumes that the coordinate point is on the disk of the Sun at the rsun radius.

If a point in the frame is off limb then NaN will be returned.

Returns

new_frame (HelioProjective) – A new frame instance with all the attributes of the original but now with a third coordinate.