ApplyBeam
Apply the LOFAR beam model, or the inverse of it.
inputs
type
- type:
string- default:
applybeam- doc:
Case-insensitive step type; must be ‘applybeam’.
beammode
- type:
enum- default:
default- doc:
Beam mode to apply, can be
array_factor,element,full, ordefault(same asfull). The modefullapplies both the element beam and the array factor.- symbols:
array_factor,element,full,default
beamproximitylimit
- type:
float- default:
60- doc:
Specified in arcseconds, and if non-zero, sources that are near each other are clustered and the beam is only calculated for each cluster. This trades an increase in speed for a very low level of loss in accuracy. This parameter is ignored in the ApplyBeam step itself, and should instead be used as part of predict, ddecal, gaincal, h5parmpredict, etc. This parameter has been introduced in Dec 2020.
coefficients_path
- type:
string- default:
""- doc:
Specifies the path of coefficients that might be needed to calculate the beam. This field is passed to EveryBeam. Not all telescope beams require coefficient files, and for example for the LOFAR beam model this field can be left empty.
direction
- type:
string- doc:
A RA/Dec value specifying in what direction to correct the beam. See
phaseshift.phasecenterfor syntax. If empty, the beam is corrected in the direction of the current phase center.
elementmodel
- type:
enum- default:
default- doc:
Specifies which beam model to use. The default value of “default” means that the model is inferred from the MS. For a LOFAR MS the default is hamaker, and for an OSKAR MS the default is oskardipole.
- symbols:
hamaker,lobes,oskarsphericalwave,oskardipole (or any other model EveryBeam supports)
invert
- type:
boolean?- default:
True- doc:
Invert the corrections, to correct the data. Default is
true. If you want to corrupt the data, set it tofalse.
onebeamperpatch
- type:
boolean- default:
False- doc:
Deprecated: use beamproximitylimit instead. When
true, computes the beam only for the center of each patch (saves computation time, but you should set this tofalsefor large patches). In the ApplyBeam step, this setting does not make sense (but it does if the applybeam is part of predict, ddecal, gaincal, h5parmpredict, etc.). Generally,falseis the right setting for this option. The default has changed to false in Nov 2018.
skipstations
- type:
string[]
default
- doc:
List of stations for which the beam should NOT be applied. This is an advanced option, for uses where the beam has previously been applied for a part of the stations. This setting does not work for dish-based telescopes.
step_name
- type:
string- default:
applybeam- doc:
unique name for the step.
updateweights
- type:
boolean?- doc:
Update the weights column, in a way consistent with the weights being inverse proportional to the autocorrelations (e.g. if ‘autoweight’ was used before).
usechannelfreq
- type:
boolean?- default:
True- doc:
Compute the beam for each channel of the measurement set separately. This is useful for merged / concatenated measurement sets. For raw LOFAR data you should set it to
false, so that the beam will be formed as in the station hardware. Also, setting it to false is faster.
usemodeldata
- type:
boolean?- default:
False- doc:
Apply the beam to the model data buffers instead of the main data buffer. The direction parameter is ignored. Instead the direction is read from the metadata added when the model data was created. For model data generated by WGridderPredict for example, the directions originate from the regions file supplied to WGridderPredict.