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Planetary constants manager.
You can use this class to build working models of Solar System bodies by loading text planetary constant files and binary orientation kernels. For a full description of how to use this, see Planetary Reference Frames.
Read frame variables from a KPL/FK file.
Appropriate files will typically have the extension .tf
or
.tpc
and will define a series of names and values that will
be loaded into this object’s .variables
dictionary.
>>> from skyfield.api import load
>>> pc = PlanetaryConstants()
>>> pc.read_text(load('moon_080317.tf'))
>>> pc.variables['FRAME_31006_NAME']
'MOON_PA_DE421'
Read binary segments descriptions from a DAF/PCK file.
Binary segments live in .bpc
files and predict how a body
like a planet or moon will be oriented on a given date.
Given a frame name, return a Frame
object.
Given a frame integer code, return a Frame
object.
Build an object representing a location on a body’s surface.
Planetary constants frame, for building rotation matrices.
Return the rotation matrix for this frame at time t
.
Return rotation and rate matrices for this frame at time t
.
The rate matrix returned is in units of angular motion per day.