PrecessedGeocentric¶
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class
astropy.coordinates.
PrecessedGeocentric
(*args, **kwargs)[source] [edit on github]¶ Bases:
astropy.coordinates.BaseRADecFrame
A coordinate frame defined in a similar manner as GCRS, but precessed to a requested (mean) equinox. Note that this does not end up the same as regular GCRS even for J2000 equinox, because the GCRS orientation is fixed to that of ICRS, which is not quite the same as the dynamical J2000 orientation.
The frame attributes are listed under Other Parameters
Parameters: representation :
BaseRepresentation
or NoneA representation object or
None
to have no data (or use the other keywords below).ra :
Angle
, optional, must be keywordThe RA for this object (
dec
must also be given andrepresentation
must be None).dec :
Angle
, optional, must be keywordThe Declination for this object (
ra
must also be given andrepresentation
must be None).distance :
Quantity
, optional, must be keywordThe Distance for this object along the line-of-sight. (
representation
must be None).pm_ra_cosdec :
Quantity
, optional, must be keywordThe proper motion in Right Ascension (including the
cos(dec)
factor) for this object (pm_dec
must also be given).pm_dec :
Quantity
, optional, must be keyword Theproper motion in Declination for this object (
pm_ra_cosdec
must also be given).radial_velocity :
Quantity
, optional, must be keywordThe radial velocity of this object.
copy : bool, optional
If
True
(default), make copies of the input coordinate arrays. Can only be passed in as a keyword argument.Other Parameters: equinox :
Time
The (mean) equinox to precess the coordinates to.
obstime :
Time
The time at which the observation is taken. Used for determining the position of the Earth.
obsgeoloc :
CartesianRepresentation
,Quantity
The position of the observer relative to the center-of-mass of the Earth, oriented the same as BCRS/ICRS. Either [0, 0, 0],
CartesianRepresentation
, or proper input for one, i.e., aQuantity
with shape (3, ...) and length units. Defaults to [0, 0, 0], meaning “true” Geocentric.obsgeovel :
CartesianRepresentation
,Quantity
The velocity of the observer relative to the center-of-mass of the Earth, oriented the same as BCRS/ICRS. Either 0,
CartesianRepresentation
, or proper input for one, i.e., aQuantity
with shape (3, ...) and velocity units. Defaults to [0, 0, 0], meaning “true” Geocentric.Attributes Summary
default_differential
default_representation
equinox
frame_attributes
frame_specific_representation_info
name
obsgeoloc
obsgeovel
obstime
Attributes Documentation
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default_differential
¶
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default_representation
¶
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equinox
= <Time object: scale='utc' format='jyear_str' value=J2000.000>¶
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frame_attributes
= OrderedDict([('equinox', <astropy.coordinates.frame_attributes.TimeFrameAttribute object>), ('obstime', <astropy.coordinates.frame_attributes.TimeFrameAttribute object>), ('obsgeoloc', <astropy.coordinates.frame_attributes.CartesianRepresentationFrameAttribute object>), ('obsgeovel', <astropy.coordinates.frame_attributes.CartesianRepresentationFrameAttribute object>)])¶
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frame_specific_representation_info
¶
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name
= 'precessedgeocentric'¶
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obsgeoloc
= <CartesianRepresentation (x, y, z) in m ( 0., 0., 0.)>¶
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obsgeovel
= <CartesianRepresentation (x, y, z) in m / s ( 0., 0., 0.)>¶
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obstime
= <Time object: scale='utc' format='jyear_str' value=J2000.000>¶
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