yaw.core.coordinates.CoordSky

class yaw.core.coordinates.CoordSky(ra: ArrayLike, dec: ArrayLike)

Bases: Coordinate

A representation of a vector of angular coordinates in radian.

Angles follow the astronomical convention of R.A./Dec., i.e. declination values are in the range of [\(-\pi\), \(\pi\)].

Create a new coordinate vector.

Parameters:

• ra (float, NDArray) – The right ascension coordinate(s).

• dec (float, NDArray) – The declination coordinate(s).

Note

The coordinate vector has a length, supports numpy-style indexing and iteration over the elements (always returning new coordinate vector instances).

Methods

__init__(ra, dec)	Create a new coordinate vector.
distance(other)	Compute the angular distance in radian between two coordinate vectors.
from_array(array)	Create a new coordinate vector from an array of tuples of (ra, dec).
from_coords(coords)	Concatenate a sequence of coordinates into a new vector of coordates.
mean()	The mean coordinate (mean over all dimensions).
to_3d()	Get the coordinates as 3-dim Euclidean coordiante Coord3D.
to_sky()	Get the coordinates as angular coordiante CoordSky in radian.

Attributes

dim	A list of names of coordinates in the coordinate system.
ndim	The number of coordinates in the coordinate system.
values	The coordinate values cast into a numpy array with shape (N, ndim) or (ndim,) if there is only a single entry.
ra	The right ascension coordinate(s).
dec	The declination coordinate(s).

dec: NDArray

The declination coordinate(s).

property dim: tuple[str]

A list of names of coordinates in the coordinate system.

distance(other: Coordinate) → DistSky

Compute the angular distance in radian between two coordinate vectors.

Coordinates are automatically converted before distance calculation.

Parameters:

other (Coordinate) – Second coordinate vector.

Returns:

Angular distance in radian between points in this and the other vector.

Return type:

DistSky

classmethod from_array(array)

Create a new coordinate vector from an array of tuples of (ra, dec).

classmethod from_coords(coords: Sequence[CoordSky]) → CoordSky

Concatenate a sequence of coordinates into a new vector of coordates.

mean() → Coord3D

The mean coordinate (mean over all dimensions).

property ndim: int

The number of coordinates in the coordinate system.

ra: NDArray

The right ascension coordinate(s).

to_3d() → Coord3D

Get the coordinates as 3-dim Euclidean coordiante Coord3D.

to_sky() → CoordSky

Get the coordinates as angular coordiante CoordSky in radian.

Warning

During conversion, points loose their radial information. After back-transformation to Coord3D they lie on the unit sphere.

property values: NDArray[np.float64]

The coordinate values cast into a numpy array with shape (N, ndim) or (ndim,) if there is only a single entry.