Reference/API

astropy.coordinates Package

This subpackage contains classes and functions for celestial coordinates of astronomical objects. It also contains a framework for conversions between coordinate systems.

Functions

angular_separation(lon1, lat1, lon2, lat2)	Angular separation between two points on a sphere.
cartesian_to_spherical(x, y, z)	Converts 3D rectangular cartesian coordinates to spherical polar coordinates.
concatenate(coords)	Combine multiple coordinate objects into a single SkyCoord.
concatenate_representations(reps)	Combine multiple representation objects into a single instance by concatenating the data in each component.
custom_stokes_symbol_mapping(mapping[, replace])	Add a custom set of mappings from values to Stokes symbols.
get_body(body, time[, location, ephemeris])	Get a SkyCoord for a solar system body as observed from a location on Earth in the GCRS reference system.
get_body_barycentric(body, time[, ephemeris])	Calculate the barycentric position of a solar system body.
get_body_barycentric_posvel(body, time[, ...])	Calculate the barycentric position and velocity of a solar system body.
get_constellation(coord[, short_name, ...])	Determines the constellation(s) a given coordinate object contains.
get_icrs_coordinates(name[, parse, cache])	Retrieve an ICRS object by using Sesame to retrieve coordinates for the specified name.
get_moon(time[, location, ephemeris])	Deprecated since version 5.3.
get_sun(time)	Determines the location of the sun at a given time (or times, if the input is an array Time object), in geocentric coordinates.
golden_spiral_grid(size)	Generate a grid of points on the surface of the unit sphere using the Fibonacci or Golden Spiral method.
make_transform_graph_docs(transform_graph)	Generates a string that can be used in other docstrings to include a transformation graph, showing the available transforms and coordinate systems.
match_coordinates_3d(matchcoord, catalogcoord)	Finds the nearest 3-dimensional matches of a coordinate or coordinates in a set of catalog coordinates.
match_coordinates_sky(matchcoord, catalogcoord)	Finds the nearest on-sky matches of a coordinate or coordinates in a set of catalog coordinates.
offset_by(lon, lat, posang, distance)	Point with the given offset from the given point.
position_angle(lon1, lat1, lon2, lat2)	Position Angle (East of North) between two points on a sphere.
search_around_3d(coords1, coords2, distlimit)	Searches for pairs of points that are at least as close as a specified distance in 3D space.
search_around_sky(coords1, coords2, seplimit)	Searches for pairs of points that have an angular separation at least as close as a specified angle.
spherical_to_cartesian(r, lat, lon)	Converts spherical polar coordinates to rectangular cartesian coordinates.
uniform_spherical_random_surface([size])	Generate a random sampling of points on the surface of the unit sphere.
uniform_spherical_random_volume([size, ...])	Generate a random sampling of points that follow a uniform volume density distribution within a sphere.

Classes

AffineTransform(transform_func, fromsys, tosys)	A coordinate transformation specified as a function that yields a 3 x 3 cartesian transformation matrix and a tuple of displacement vectors.
AltAz(*args, **kwargs)	A coordinate or frame in the Altitude-Azimuth system (Horizontal coordinates) with respect to the WGS84 ellipsoid.
Angle(angle[, unit, dtype, copy])	One or more angular value(s) with units equivalent to radians or degrees.
Attribute([default, secondary_attribute, doc])	A non-mutable data descriptor to hold a frame attribute.
BarycentricMeanEcliptic(*args[, copy, ...])	Barycentric mean ecliptic coordinates.
BarycentricTrueEcliptic(*args[, copy, ...])	Barycentric true ecliptic coordinates.
BaseAffineTransform(fromsys, tosys[, ...])	Base class for common functionality between the AffineTransform-type subclasses.
BaseBodycentricRepresentation(lon[, lat, ...])	Representation of points in bodycentric 3D coordinates.
BaseCoordinateFrame(*args[, copy, ...])	The base class for coordinate frames.
BaseDifferential(*args, **kwargs)	A base class representing differentials of representations.
BaseEclipticFrame(*args[, copy, ...])	A base class for frames that have names and conventions like that of ecliptic frames.
BaseGeodeticRepresentation(lon[, lat, ...])	Base class for geodetic representations.
BaseRADecFrame(*args[, copy, ...])	A base class that defines default representation info for frames that represent longitude and latitude as Right Ascension and Declination following typical "equatorial" conventions.
BaseRepresentation(*args[, differentials])	Base for representing a point in a 3D coordinate system.
BaseRepresentationOrDifferential(*args, **kwargs)	3D coordinate representations and differentials.
BaseSphericalCosLatDifferential(*args, **kwargs)	Differentials from points on a spherical base representation.
BaseSphericalDifferential(*args, **kwargs)
BoundsError	Raised when an angle is outside of its user-specified bounds.
CIRS(*args[, copy, representation_type, ...])	A coordinate or frame in the Celestial Intermediate Reference System (CIRS).
CartesianDifferential(d_x[, d_y, d_z, unit, ...])	Differentials in of points in 3D cartesian coordinates.
CartesianRepresentation(x[, y, z, unit, ...])	Representation of points in 3D cartesian coordinates.
CartesianRepresentationAttribute([default, ...])	A frame attribute that is a CartesianRepresentation with specified units.
CompositeTransform(transforms, fromsys, tosys)	A transformation constructed by combining together a series of single-step transformations.
ConvertError	Raised if a coordinate system cannot be converted to another.
CoordinateAttribute(frame[, default, ...])	A frame attribute which is a coordinate object.
CoordinateTransform(fromsys, tosys[, ...])	An object that transforms a coordinate from one system to another.
CustomBarycentricEcliptic(*args[, copy, ...])	Barycentric ecliptic coordinates with custom obliquity.
CylindricalDifferential(d_rho[, d_phi, d_z, ...])	Differential(s) of points in cylindrical coordinates.
CylindricalRepresentation(rho[, phi, z, ...])	Representation of points in 3D cylindrical coordinates.
DifferentialAttribute([default, ...])	A frame attribute which is a differential instance.
Distance([value, unit, z, cosmology, ...])	A one-dimensional distance.
DynamicMatrixTransform(matrix_func, fromsys, ...)	A coordinate transformation specified as a function that yields a 3 x 3 cartesian transformation matrix.
EarthLocation(*args, **kwargs)	Location on the Earth.
EarthLocationAttribute([default, ...])	A frame attribute that can act as a EarthLocation.
FK4(*args[, copy, representation_type, ...])	A coordinate or frame in the FK4 system.
FK4NoETerms(*args[, copy, ...])	A coordinate or frame in the FK4 system, but with the E-terms of aberration removed.
FK5(*args[, copy, representation_type, ...])	A coordinate or frame in the FK5 system.
FunctionTransform(func, fromsys, tosys[, ...])	A coordinate transformation defined by a function that accepts a coordinate object and returns the transformed coordinate object.
FunctionTransformWithFiniteDifference(func, ...)	Transformation based on functions using finite difference for velocities.
GCRS(*args[, copy, representation_type, ...])	A coordinate or frame in the Geocentric Celestial Reference System (GCRS).
GRS80GeodeticRepresentation(lon[, lat, ...])	Representation of points in GRS80 3D geodetic coordinates.
Galactic(*args[, copy, representation_type, ...])	A coordinate or frame in the Galactic coordinate system.
GalacticLSR(*args[, copy, ...])	A coordinate or frame in the Local Standard of Rest (LSR), axis-aligned to the Galactic frame.
Galactocentric(*args, **kwargs)	A coordinate or frame in the Galactocentric system.
GenericFrame(frame_attrs)	A frame object that can't store data but can hold any arbitrary frame attributes.
GeocentricMeanEcliptic(*args[, copy, ...])	Geocentric mean ecliptic coordinates.
GeocentricTrueEcliptic(*args[, copy, ...])	Geocentric true ecliptic coordinates.
HADec(*args, **kwargs)	A coordinate or frame in the Hour Angle-Declination system (Equatorial coordinates) with respect to the WGS84 ellipsoid.
HCRS(*args[, copy, representation_type, ...])	A coordinate or frame in a Heliocentric system, with axes aligned to ICRS.
HeliocentricEclipticIAU76(*args[, copy, ...])	Heliocentric mean (IAU 1976) ecliptic coordinates.
HeliocentricMeanEcliptic(*args[, copy, ...])	Heliocentric mean ecliptic coordinates.
HeliocentricTrueEcliptic(*args[, copy, ...])	Heliocentric true ecliptic coordinates.
ICRS(*args[, copy, representation_type, ...])	A coordinate or frame in the ICRS system.
ITRS(*args[, copy, representation_type, ...])	A coordinate or frame in the International Terrestrial Reference System (ITRS).
IllegalHourError(hour)	Raised when an hour value is not in the range [0,24).
IllegalHourWarning(hour[, alternativeactionstr])	Raised when an hour value is 24.
IllegalMinuteError(minute)	Raised when an minute value is not in the range [0,60].
IllegalMinuteWarning(minute[, ...])	Raised when a minute value is 60.
IllegalSecondError(second)	Raised when an second value (time) is not in the range [0,60].
IllegalSecondWarning(second[, ...])	Raised when a second value is 60.
LSR(*args[, copy, representation_type, ...])	A coordinate or frame in the Local Standard of Rest (LSR).
LSRD(*args[, copy, representation_type, ...])	A coordinate or frame in the Dynamical Local Standard of Rest (LSRD).
LSRK(*args[, copy, representation_type, ...])	A coordinate or frame in the Kinematic Local Standard of Rest (LSR).
Latitude(angle[, unit])	Latitude-like angle(s) which must be in the range -90 to +90 deg.
Longitude(angle[, unit, wrap_angle])	Longitude-like angle(s) which are wrapped within a contiguous 360 degree range.
NonRotationTransformationError(frame_to, ...)	Raised for transformations that are not simple rotations.
NonRotationTransformationWarning(frame_to, ...)	Emitted for transformations that are not simple rotations.
PhysicsSphericalDifferential(d_phi[, ...])	Differential(s) of 3D spherical coordinates using physics convention.
PhysicsSphericalRepresentation(phi[, theta, ...])	Representation of points in 3D spherical coordinates (using the physics convention of using phi and theta for azimuth and inclination from the pole).
PrecessedGeocentric(*args[, copy, ...])	A coordinate frame defined in a similar manner as GCRS, but precessed to a requested (mean) equinox.
QuantityAttribute([default, ...])	A frame attribute that is a quantity with specified units and shape (optionally).
RadialDifferential(*args, **kwargs)	Differential(s) of radial distances.
RadialRepresentation(distance[, ...])	Representation of the distance of points from the origin.
RangeError	Raised when some part of an angle is out of its valid range.
RepresentationMapping(reprname, framename[, ...])	This NamedTuple is used with the frame_specific_representation_info attribute to tell frames what attribute names (and default units) to use for a particular representation.
SkyCoord(*args[, copy])	High-level object providing a flexible interface for celestial coordinate representation, manipulation, and transformation between systems.
SkyCoordInfo([bound])	Container for meta information like name, description, format.
SkyOffsetFrame(*args, **kwargs)	A frame which is relative to some specific position and oriented to match its frame.
SpectralCoord(value[, unit, observer, ...])	A spectral coordinate with its corresponding unit.
SpectralQuantity(value[, unit, ...])	One or more value(s) with spectral units.
SphericalCosLatDifferential(d_lon_coslat[, ...])	Differential(s) of points in 3D spherical coordinates.
SphericalDifferential(d_lon[, d_lat, ...])	Differential(s) of points in 3D spherical coordinates.
SphericalRepresentation(lon[, lat, ...])	Representation of points in 3D spherical coordinates.
StaticMatrixTransform(matrix, fromsys, tosys)	A coordinate transformation defined as a 3 x 3 cartesian transformation matrix.
StokesCoord(stokes[, copy])	A representation of stokes coordinates with helpers for converting to profile names.
StokesSymbol([symbol, description])	Symbol for a Stokes coordinate.
Supergalactic(*args[, copy, ...])	Supergalactic Coordinates (see Lahav et al. 2000, <https://ui.adsabs.harvard.edu/abs/2000MNRAS.312..166L>, and references therein).
TEME(*args[, copy, representation_type, ...])	A coordinate or frame in the True Equator Mean Equinox frame (TEME).
TETE(*args[, copy, representation_type, ...])	An equatorial coordinate or frame using the True Equator and True Equinox (TETE).
TimeAttribute([default, ...])	Frame attribute descriptor for quantities that are Time objects.
TransformGraph()	A graph representing the paths between coordinate frames.
UnitSphericalCosLatDifferential(d_lon_coslat)	Differential(s) of points on a unit sphere.
UnitSphericalDifferential(d_lon[, d_lat, copy])	Differential(s) of points on a unit sphere.
UnitSphericalRepresentation(lon[, lat, ...])	Representation of points on a unit sphere.
UnknownSiteException(site, attribute[, ...])
WGS72GeodeticRepresentation(lon[, lat, ...])	Representation of points in WGS72 3D geodetic coordinates.
WGS84GeodeticRepresentation(lon[, lat, ...])	Representation of points in WGS84 3D geodetic coordinates.
galactocentric_frame_defaults()	Global setting of default values for the frame attributes in the Galactocentric frame.
solar_system_ephemeris()	Default ephemerides for calculating positions of Solar-System bodies.

Class Inheritance Diagram