StateBase¶

class sbpy.dynamics.state.StateBase(r: Quantity, v: Quantity, t: Quantity | Time, frame: FrameInputTypes | None = None)[source]¶

Bases: ABC

Abstract base class for dynamical state.

Parameters:

rQuantity: Position (x, y, z), shape = (3,) or (N, 3).
vQuantity: Velocity (x, y, z), shape = (3,) or (N, 3).
tTime or Quantity: Time, a scalar or shape = (N,). Time as a Quantity may only be used with the ArbitraryFrame coordinate frame.
frameBaseCoordinateFrame class or string, optional: Reference frame for r and v. Default: ArbitraryFrame.

Notes

State data is immutable.

Examples

>>> from astropy.time import Time
>>> import astropy.units as u
>>> from sbpy.dynamics import State
>>> r = [1e9, 1e9, 0] * u.km
>>> v = [0, 0, 10] * u.km / u.s
>>> t = Time("2022-07-24", scale="tdb")
>>> state = State(r, v, t)

Or, specify time relative to an arbitrary epoch:

>>> t = 327 * u.day
>>> state = State(r, v, t)

Dynamical state.

Parameters:

rQuantity: Position (x, y, z), shape = (3,) or (N, 3).
vQuantity: Velocity (x, y, z), shape = (3,) or (N, 3).
tTime or Quantity: Time, a scalar or shape = (N,). Time as a Quantity may only be used with the ArbitraryFrame coordinate frame.
frameBaseCoordinateFrame class or string, optional: Reference frame for r and v. Default: ArbitraryFrame.

Notes

State data is immutable.

Examples

>>> from astropy.time import Time
>>> import astropy.units as u
>>> from sbpy.dynamics import State
>>> r = [1e9, 1e9, 0] * u.km
>>> v = [0, 0, 10] * u.km / u.s
>>> t = Time("2022-07-24", scale="tdb")
>>> state = State(r, v, t)

Or, specify time relative to an arbitrary epoch:

>>> t = 327 * u.day
>>> state = State(r, v, t)

Attributes Summary

`arbitrary_time`	True if the time attribute is arbitrary.
`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

`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.

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

to_skycoord() → SkyCoord[source]¶: Convert to a SkyCoord object.

transform_to(frame: FrameInputTypes) → Self[source]¶

Transform state into another reference frame.

Parameters:

framestring or BaseCoordinateFrame: Transform into this reference frame.

Returns:

stateState: The transformed state.

Navigation

StateBase¶