Trajectory¶

class heliopy.spice.Trajectory(target)¶

Bases: object

A generic class for the trajectory of a single body.

Objects are initially created using only the body. To perform the actual trajectory calculation run generate_positions(). The generated positions are then available via. the attributes times, x, y, and z.

Parameters:	spacecraft (str) – Name of the target. The name must be present in the loaded kernels.

Notes

When an instance of this class is created, a leapseconds kernel and a planets kernel are both automatically loaded.

See also

furnish: for loading in local spice kernels.

Attributes Summary

`generated`	`True` if positions have been generated, `False` otherwise.
`observing_body`	Observing body.
`r`	Magnitude of position vectors.
`target`	The body whose coordinates are being calculated.
`times`	The list of datetime at which positions were last sampled.
`x`	x coordinates of position.
`y`	y coordinates of position.
`z`	z coordinates of position.

Methods Summary

`change_units`(unit)	Convert the positions to different units.
`generate_positions`(times, observing_body, frame)	Generate positions from a spice kernel.

Attributes Documentation

generated¶: True if positions have been generated, False otherwise.

observing_body¶: Observing body. The position vectors are all specified relative to this body.

r¶: Magnitude of position vectors.

target¶: The body whose coordinates are being calculated.

times¶: The list of datetime at which positions were last sampled.

x¶: x coordinates of position.

y¶: y coordinates of position.

z¶: z coordinates of position.

Methods Documentation

change_units(unit)¶

Convert the positions to different units.

Parameters:	unit (astropy.units.Quantity) – Must be a unit of length (e.g. km, m, AU).

generate_positions(times, observing_body, frame)¶

Generate positions from a spice kernel.

Parameters:

Parameters:	times (iterable of datetime) – An iterable (e.g. a list) of datetime objects at which the positions are calculated. observing_body (str) – The observing body. Output position vectors are given relative to the position of this body. See https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/req/naif_ids.html for a list of bodies. frame (str) – The coordinate system to return the positions in. See https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/req/frames.html for a list of frames.

times (iterable of datetime) – An iterable (e.g. a list) of datetime objects at which the positions are calculated.
observing_body (str) – The observing body. Output position vectors are given relative to the position of this body. See https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/req/naif_ids.html for a list of bodies.
frame (str) – The coordinate system to return the positions in. See https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/req/frames.html for a list of frames.