API Reference — Planetary reference frames¶
- class skyfield.planetarylib.PlanetaryConstants¶
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_text(file)¶
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(file)¶
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.
- build_latlon_degrees(frame, latitude_degrees, longitude_degrees, elevation_m=0.0)¶
Build an object representing a location on a body’s surface.
- class skyfield.planetarylib.Frame(center, segment, matrix)¶
Planetary constants frame, for building rotation matrices.
- rotation_at(t)¶
Return the rotation matrix for this frame at time
t
.
- rotation_and_rate_at(t)¶
Return rotation and rate matrices for this frame at time
t
.The rate matrix returned is in units of angular motion per day.