orca.transform.dftspectrum
Direct Fourier Transform spectrum extraction.
Provides functions for phase-shifting visibility data to extract spectra at arbitrary sky positions using DFT techniques. This allows extracting spectra for sources that are not at the phase center.
Functions
- phase_shift_vis
Phase shift visibility data to a new sky position.
- dftspectrum
Compute DFT spectrum at specified positions (not yet implemented).
- phase_data_to_pos_inplace
In-place phase shift of visibility data array.
Notes
INVERSE_C_MS is 1/c in units of seconds per meter (3.3356e-9 s/m).
Attributes
Functions
|
Phase shift visibility data column and return the shifted data. It does not write back to the table, nor does it |
|
|
|
Module Contents
- orca.transform.dftspectrum.phase_shift_vis(t: casacore.tables.table, freqs: numpy.ndarray, phase_center: astropy.coordinates.SkyCoord, pos: astropy.coordinates.SkyCoord, columnname: str, startrow: int = 0, nrow: int = -1, rowincr: int = 1) numpy.ndarray[source]
Phase shift visibility data column and return the shifted data. It does not write back to the table, nor does it shift the UVW coordinates. Only works with data with one spectral window.
- Parameters:
t – table containing the data
freqs – (1, N_chan) channel array. Can get from tspw.getcol(‘CHAN_FREQ’).
phase_center – current phase center.
pos – position to shift to.
columnname – column name for the data.
startrow – see casacore getcol documentation.
nrow – see casacore getcol documentation.
rowincr – see casacore getcol documentation.
Returns: the phased shifted data
- orca.transform.dftspectrum.dftspectrum(data: numpy.ndarray, uvw: numpy.ndarray, freqs: numpy.ndarray, ra0_rad: float, dec0_rad: float, ra_rad: numpy.ndarray, dec_rad: numpy.ndarray, weights: numpy.ndarray | None = None)[source]
- orca.transform.dftspectrum.phase_data_to_pos_inplace(data: numpy.ndarray, uvw: numpy.ndarray, freqs: numpy.ndarray, ra0_rad: float, dec0_rad: float, ra_rad: float, dec_rad: float)[source]