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image.restoringbeam - Function

1.1.1 Get the restoring beam(s).


Description

This function gets the restoring beam(s), if any. If the image has a traditional restoring beam, that is returned no matter what channel and polarization are set to. If the image has per-plane beams and at least one of channel or polarization is set to a non-negative value, the beam for that particular plane is returned. In both these cases, the returned record contains fields ’major’, ’minor’ and ’postionangle’. Each of these fields contains a quantity.

If the image contains multiple beams and both channel and polarization are negative, a record containing all the beams is returned. This record contains three fields. ”nChannels” contains an integer value equal to the number of channels, ”nStokes” contains an integer value equal to the number of polarizations, and ”beams” contains a record of information for all beams. If the image has no polarization axis or no spectral axis, the fields in the ”beams” record run from ”*0” to the number of spectral channels or number of polarizations less one, eg ”*31” for an image with 32 channels. Each of these fields references a beam subrecord with the structure described above for a single beam.

If the image contains both a spectral axis and a polarization axis, the record returned contains fields running from ”*0” to the number of spectral channels less one, eg ”*31” for an image with 32 spectral channels. Each of these fields has an associated subrecord with fields running from ”*0” to the number of polarizations less one, eg ”*3” in an image with 4 polarizations. Each one of those fields is associated with a beam record for that corresponding channel and polarization. The beam record has a structure described above for a single beam.

If there is no restoring beam, this function returds an empty record.

You can set the restoring beam with function setrestoringbeam.

Arguments





Inputs

channel

The zero-based spectral channel number for a per-plane beam. Default -1

allowed:

int

Default:

-1

polarization

The zero-based polarization plane number for a per-plane beam. Default -1

allowed:

int

Default:

-1

Returns
record

Example

 
 
"""  
#  
print "\t----\t restoringbeam Ex 1 \t----"  
ia.maketestimage()  
print ia.restoringbeam()  
#{’major’: {’unit’: ’arcsec’, ’value’: 53.500004857778549},  
# ’minor’: {’unit’: ’arcsec’, ’value’: 34.199998900294304},  
# ’positionangle’: {’unit’: ’deg’, ’value’: 6.0}}  
ia.close()  
#  
"""  
 

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