API Reference — Orbital Elements¶

skyfield.elementslib.osculating_elements_of(position, reference_frame=None, gm_km3_s2=None)¶

Produce the osculating orbital elements for a position.

position is an instance of ICRF. These are commonly returned by the at() method of any Solar System body. reference_frame is an optional argument and is a 3x3 numpy array. The reference frame by default is the ICRF. Commonly used reference frames are found in skyfield.data.spice.inertial_frames. gm_km3_s2 is an optional float argument representing the gravitational parameter (G*M) in units of km^3/s^2, which is the sum of the masses of the orbiting object and the object being orbited. If not specified, this is calculated for you.

This function returns an instance of OsculatingElements

class skyfield.elementslib.OsculatingElements(position, velocity, time, mu_km_s)¶

One or more sets of osculating orbital elements.

An OsculatingElements object can be initialized with the following parameters:

position : Distance object

Position vector with shape (3,) or (3, n)

velocity : Velocity object

Velocity vector with shape (3,) or (3, n)

time: Time object

The times of the position and velocity vectors

mu_km_s: float

Gravitational parameter (G*M) in units of km^3/s^2