Galactic¶
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class
astropy.coordinates.
Galactic
(*args, **kwargs)[source] [edit on github]¶ Bases:
astropy.coordinates.BaseCoordinateFrame
A coordinate or frame in the Galactic coordinate system.
This frame is used in a variety of Galactic contexts because it has as its x-y plane the plane of the Milky Way. The positive x direction (i.e., the l=0, b=0 direction) points to the center of the Milky Way and the z-axis points toward the North Galactic Pole (following the IAU’s 1958 definition [R7]). However, unlike the
Galactocentric
frame, the origin of this frame in 3D space is the solar system barycenter, not the center of the Milky Way.Parameters: representation :
BaseRepresentation
or NoneA representation object or None to have no data (or use the other keywords)
l :
Angle
, optional, must be keywordThe Galactic longitude for this object (
b
must also be given andrepresentation
must be None).b :
Angle
, optional, must be keywordThe Galactic latitude for this object (
l
must also be given andrepresentation
must be None).distance :
Quantity
, optional, must be keywordThe Distance for this object along the line-of-sight.
pm_l_cosb :
Quantity
, optional, must be keywordThe proper motion in Galactic longitude (including the
cos(b)
term) for this object (pm_b
must also be given).pm_b :
Quantity
, optional, must be keywordThe proper motion in Galactic latitude for this object (
pm_l_cosb
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.differential_cls :
BaseDifferential
, dict, optionalA differential class or dictionary of differential classes (currently only a velocity differential with key ‘s’ is supported). This sets the expected input differential class, thereby changing the expected keyword arguments of the data passed in. For example, passing
differential_cls=CartesianDifferential
will make the classes expect velocity data with the argument namesv_x, v_y, v_z
.Notes
[R7] Blaauw, A.; Gum, C. S.; Pawsey, J. L.; Westerhout, G. (1960), “The new I.A.U. system of galactic coordinates (1958 revision),” MNRAS, Vol 121, pp.123. Attributes Summary
default_differential
default_representation
frame_specific_representation_info
name
Attributes Documentation
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default_differential
¶
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default_representation
¶
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frame_specific_representation_info
¶
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name
= 'galactic'¶
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