Coordinate Transforms#
Numpy#
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Converts Right-Ascension/Declination coordinates in radians to a Direction Cosine lm coordinates, relative to the Phase Centre. |
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Converts Right-Ascension/Declination coordinates in radians to a Direction Cosine lm coordinates, relative to the Phase Centre. |
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Convert Direction Cosine lm coordinates to Right Ascension/Declination coordinates in radians, relative to the Phase Centre. |
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Convert Direction Cosine lm coordinates to Right Ascension/Declination coordinates in radians, relative to the Phase Centre. |
- africanus.coordinates.radec_to_lm(radec, phase_centre=None)[source]#
Converts Right-Ascension/Declination coordinates in radians to a Direction Cosine lm coordinates, relative to the Phase Centre.
\begin{eqnarray} & l =& \, \cos \, \delta \sin \, \Delta \alpha \\ & m =& \, \sin \, \delta \cos \, \delta 0 - \cos \delta \sin \delta 0 \cos \Delta \alpha \\ & n =& \, \sqrt{1 - l^2 - m^2} - 1 \end{eqnarray}where \(\Delta \alpha = \alpha - \alpha 0\) is the difference between the Right Ascension of each coordinate and the phase centre and \(\delta 0\) is the Declination of the phase centre.
- Parameters:
- radec
numpy.ndarray
radec coordinates of shape
(coord, 2)
where Right-Ascension and Declination are in the last 2 components, respectively.- phase_centre
numpy.ndarray
, optional radec coordinates of the Phase Centre. Shape
(2,)
- radec
- Returns:
numpy.ndarray
lm Direction Cosines of shape
(coord, 2)
- africanus.coordinates.radec_to_lmn(radec, phase_centre=None)[source]#
Converts Right-Ascension/Declination coordinates in radians to a Direction Cosine lm coordinates, relative to the Phase Centre.
\begin{eqnarray} & l =& \, \cos \, \delta \sin \, \Delta \alpha \\ & m =& \, \sin \, \delta \cos \, \delta 0 - \cos \delta \sin \delta 0 \cos \Delta \alpha \\ & n =& \, \sqrt{1 - l^2 - m^2} - 1 \end{eqnarray}where \(\Delta \alpha = \alpha - \alpha 0\) is the difference between the Right Ascension of each coordinate and the phase centre and \(\delta 0\) is the Declination of the phase centre.
- Parameters:
- radec
numpy.ndarray
radec coordinates of shape
(coord, 2)
where Right-Ascension and Declination are in the last 2 components, respectively.- phase_centre
numpy.ndarray
, optional radec coordinates of the Phase Centre. Shape
(2,)
- radec
- Returns:
numpy.ndarray
lm Direction Cosines of shape
(coord, 3)
- africanus.coordinates.lm_to_radec(lm, phase_centre=None)[source]#
Convert Direction Cosine lm coordinates to Right Ascension/Declination coordinates in radians, relative to the Phase Centre.
\begin{eqnarray} & \delta = & \, \arcsin \left( m \cos \delta 0 + n \sin \delta 0 \right) \\ & \alpha = & \, \arctan \left( \frac{l}{n \cos \delta 0 - m \sin \delta 0} \right) \\ \end{eqnarray}where \(\alpha\) is the Right Ascension of each coordinate and the phase centre and \(\delta 0\) is the Declination of the phase centre.
- Parameters:
- lm
numpy.ndarray
lm Direction Cosines of shape
(coord, 2)
- phase_centre
numpy.ndarray
, optional radec coordinates of the Phase Centre. Shape
(2,)
- lm
- Returns:
numpy.ndarray
radec coordinates of shape
(coord, 2)
where Right-Ascension and Declination are in the last 2 components, respectively.
- africanus.coordinates.lmn_to_radec(lmn, phase_centre=None)[source]#
Convert Direction Cosine lm coordinates to Right Ascension/Declination coordinates in radians, relative to the Phase Centre.
\begin{eqnarray} & \delta = & \, \arcsin \left( m \cos \delta 0 + n \sin \delta 0 \right) \\ & \alpha = & \, \arctan \left( \frac{l}{n \cos \delta 0 - m \sin \delta 0} \right) \\ \end{eqnarray}where \(\alpha\) is the Right Ascension of each coordinate and the phase centre and \(\delta 0\) is the Declination of the phase centre.
- Parameters:
- lmn
numpy.ndarray
lm Direction Cosines of shape
(coord, 3)
- phase_centre
numpy.ndarray
, optional radec coordinates of the Phase Centre. Shape
(2,)
- lmn
- Returns:
numpy.ndarray
radec coordinates of shape
(coord, 2)
where Right-Ascension and Declination are in the last 2 components, respectively.
Dask#
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Converts Right-Ascension/Declination coordinates in radians to a Direction Cosine lm coordinates, relative to the Phase Centre. |
|
Converts Right-Ascension/Declination coordinates in radians to a Direction Cosine lm coordinates, relative to the Phase Centre. |
|
Convert Direction Cosine lm coordinates to Right Ascension/Declination coordinates in radians, relative to the Phase Centre. |
|
Convert Direction Cosine lm coordinates to Right Ascension/Declination coordinates in radians, relative to the Phase Centre. |
- africanus.coordinates.dask.radec_to_lm(radec, phase_centre=None)[source]#
Converts Right-Ascension/Declination coordinates in radians to a Direction Cosine lm coordinates, relative to the Phase Centre.
\begin{eqnarray} & l =& \, \cos \, \delta \sin \, \Delta \alpha \\ & m =& \, \sin \, \delta \cos \, \delta 0 - \cos \delta \sin \delta 0 \cos \Delta \alpha \\ & n =& \, \sqrt{1 - l^2 - m^2} - 1 \end{eqnarray}where \(\Delta \alpha = \alpha - \alpha 0\) is the difference between the Right Ascension of each coordinate and the phase centre and \(\delta 0\) is the Declination of the phase centre.
- Parameters:
- radec
dask.array.Array
radec coordinates of shape
(coord, 2)
where Right-Ascension and Declination are in the last 2 components, respectively.- phase_centre
dask.array.Array
, optional radec coordinates of the Phase Centre. Shape
(2,)
- radec
- Returns:
dask.array.Array
lm Direction Cosines of shape
(coord, 2)
- africanus.coordinates.dask.radec_to_lmn(radec, phase_centre=None)[source]#
Converts Right-Ascension/Declination coordinates in radians to a Direction Cosine lm coordinates, relative to the Phase Centre.
\begin{eqnarray} & l =& \, \cos \, \delta \sin \, \Delta \alpha \\ & m =& \, \sin \, \delta \cos \, \delta 0 - \cos \delta \sin \delta 0 \cos \Delta \alpha \\ & n =& \, \sqrt{1 - l^2 - m^2} - 1 \end{eqnarray}where \(\Delta \alpha = \alpha - \alpha 0\) is the difference between the Right Ascension of each coordinate and the phase centre and \(\delta 0\) is the Declination of the phase centre.
- Parameters:
- radec
dask.array.Array
radec coordinates of shape
(coord, 2)
where Right-Ascension and Declination are in the last 2 components, respectively.- phase_centre
dask.array.Array
, optional radec coordinates of the Phase Centre. Shape
(2,)
- radec
- Returns:
dask.array.Array
lm Direction Cosines of shape
(coord, 3)
- africanus.coordinates.dask.lm_to_radec(lm, phase_centre=None)[source]#
Convert Direction Cosine lm coordinates to Right Ascension/Declination coordinates in radians, relative to the Phase Centre.
\begin{eqnarray} & \delta = & \, \arcsin \left( m \cos \delta 0 + n \sin \delta 0 \right) \\ & \alpha = & \, \arctan \left( \frac{l}{n \cos \delta 0 - m \sin \delta 0} \right) \\ \end{eqnarray}where \(\alpha\) is the Right Ascension of each coordinate and the phase centre and \(\delta 0\) is the Declination of the phase centre.
- Parameters:
- lm
dask.array.Array
lm Direction Cosines of shape
(coord, 2)
- phase_centre
dask.array.Array
, optional radec coordinates of the Phase Centre. Shape
(2,)
- lm
- Returns:
dask.array.Array
radec coordinates of shape
(coord, 2)
where Right-Ascension and Declination are in the last 2 components, respectively.
- africanus.coordinates.dask.lmn_to_radec(lmn, phase_centre=None)[source]#
Convert Direction Cosine lm coordinates to Right Ascension/Declination coordinates in radians, relative to the Phase Centre.
\begin{eqnarray} & \delta = & \, \arcsin \left( m \cos \delta 0 + n \sin \delta 0 \right) \\ & \alpha = & \, \arctan \left( \frac{l}{n \cos \delta 0 - m \sin \delta 0} \right) \\ \end{eqnarray}where \(\alpha\) is the Right Ascension of each coordinate and the phase centre and \(\delta 0\) is the Declination of the phase centre.
- Parameters:
- lmn
dask.array.Array
lm Direction Cosines of shape
(coord, 3)
- phase_centre
dask.array.Array
, optional radec coordinates of the Phase Centre. Shape
(2,)
- lmn
- Returns:
dask.array.Array
radec coordinates of shape
(coord, 2)
where Right-Ascension and Declination are in the last 2 components, respectively.