SourceOrbit

class sbpy.dynamics.syndynes.SourceOrbit(source: State, dt: Quantity, r: Quantity, v: Quantity, t: Time, observer: State | None = None)

Bases: SynStates

Collection of states that make up an orbit.

Parameters:

sourceState

The orbit is for this source state.

dtQuantity

Each point’s time relative to the observation time, shape = (N,).

rQuantity

Position (x, y, z), shape = (N, 3). Same coordinate frame as source.

vQuantity

Velocity (x, y, z), shape = (N, 3). Same coordinate frame as source.

tTime or Quantity

Time of observation.

observerState, optional

The observer, used to generate sky coordinates.

Attributes Summary

arbitrary_time	True if the time attribute is arbitrary.
dt
epoch	Epoch of each orbit point.
frame
r	Position vector.
rv	Position in km, and velocity in km/s.
t	Time.
v	Velocity vector.
v_x	x component of the velocity vector.
v_y	y component of the velocity vector.
v_z	z component of the velocity vector.
x	x component of the position vector.
y	y component of the position vector.
z	z component of the position vector.

Methods Summary

plot([ax, wcs, unit])	Plot the coordinates.
to_ephem()	Convert to an sbpy ephemeris object.
to_skycoord()	Convert to a SkyCoord object.
transform_to(frame)	Transform state into another reference frame.

Attributes Documentation

arbitrary_time

True if the time attribute is arbitrary.

dt

epoch

Epoch of each orbit point.

frame

r

Position vector.

rv

Position in km, and velocity in km/s.

t

Time.

v

Velocity vector.

v_x

x component of the velocity vector.

v_y

y component of the velocity vector.

v_z

z component of the velocity vector.

x

x component of the position vector.

y

y component of the position vector.

z

z component of the position vector.

Methods Documentation

plot(ax: Axes | None = None, *, wcs: WCS | None = None, unit: Unit | str = 'arcsec', **kwargs) → None

Plot the coordinates.

Requires self.observer.

Parameters:

axAxes, optional

Plot to this axis object.

wcsWCS, optional

Transform coordinates to the image plane using this world coordinate system object.

unitUnit or str, optional

Plot in these angular units.

**kwargsdict

Keyword arguments are passed along to ax.plot.

to_ephem() → Ephem

Convert to an sbpy ephemeris object.

Returns:

ephEphem

Notes

Source and observer states are stored in the Ephem.meta attribute.

Attribute or quantity	Ephem field name
beta(s)	beta_rad
age(s)	age
t, as Time	date
t, as Quantity	t_relative
\(|r|\)	r
\(|v \cdot \hat{r}|\)	rdot
coords.ra	ra
coords.dec	dec
coords.pm_ra_cosdec	ra*cos(dec)_rate
coords.pm_dec	dec_rate
coords.lon	lon
coords.lat	lat
coords.pm_lon_coslat	lon*cos(lat)_rate
coords.pm_lat	lat_rate
coords.distance	delta
coords.radial_velocity	deltadot
x	x
y	y
z	z
v_x	vx
v_y	vy
v_z	vz
initial.x	x initial
initial.y	y initial
initial.z	z initial
initial.v_x	vx initial
initial.v_y	vy initial
initial.v_z	vz initial
initial.t	t initial

to_skycoord() → SkyCoord

Convert to a SkyCoord object.

transform_to(frame: FrameInputTypes) → StateBaseType

Transform state into another reference frame.

Parameters:

framestr or BaseCoordinateFrame

Transform into this reference frame.

Returns:

stateState

The transformed state.