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========================================
API Reference — Astronomical Positions
========================================
See `positions` for a detailed guide
to these various kinds of position that Skyfield can compute,
and to the selection of coordinate systems
that can be used to express them.
.. testsetup::
from __future__ import print_function
from skyfield.api import load
from skyfield.positionlib import ICRF
ts = load.timescale()
de421 = load('de421.bsp')
earth = de421['Earth']
mars = de421['Mars']
.. currentmodule:: skyfield.positionlib
Generic ICRF position
=====================
.. autoclass:: ICRF
:members:
.. attribute:: t
The `Time` coordinate of this position.
.. attribute:: position
A `Distance` object offering the position’s |xyz| coordinates.
.. attribute:: velocity
A `Velocity` object
offering the velocity’s (\ *dx/dt,dy/dt,dz/dt*\ ) coordinates.
This attribute will have the value ``None`` if no velocity was
specified for this position.
Position measured from the Solar System barycenter
==================================================
.. autoclass:: Barycentric
:members:
This class inherits the methods of is parent class :class:`ICRF` as
well as the orientation of its axes in space.
Astrometric position relative to an observer
============================================
.. autoclass:: Astrometric
:members:
This class inherits the methods of is parent class :class:`ICRF` as
well as the orientation of its axes in space.
Apparent position relative to an observer
=========================================
.. autoclass:: Apparent
:members:
This class inherits the methods of is parent class :class:`ICRF` as
well as the orientation of its axes in space.
Geocentric position relative to the Earth
=========================================
.. autoclass:: Geocentric
:members:
This class inherits the methods of is parent class :class:`ICRF` as
well as the orientation of its axes in space.
Building a position from right ascension and declination
========================================================
.. autofunction:: position_of_radec
The position of the Solar System Barycenter
===========================================
.. autoclass:: SSB
:members:
|
