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