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imager.fitpsf - Function

2.3.1 Fit the point spread function, making psf image first if needed


Description

This fits an elliptical Gaussian to the point spread function and returns the fitted beam parameters. If psf image is not specified then a psf is made and used. The values for the beam fit are saved internally and used whenever needed (for example in the functions restore or smooth) until invalidated. The values are invalidated by selectvis, defineimage or any tool function that changes the weights. Use the function summary to check if there is a valid fitted psf stored internally.

Arguments





Outputs

bmaj

Major axis of beam

allowed:

record

Default:

bmin

Minor axis of beam

allowed:

record

Default:

bpa

Position angle of beam

allowed:

record

Default:

Inputs

psf

Name of input psf

allowed:

string

Default:

async

Run asynchronously in the background

allowed:

bool

Default:

false

Returns
bool

Example

 
 
im.makeimage(type=’psf’, image=’3C273XC1.psf’)  
params=im.fitpsf(’3C273XC1.psf’)  
#This returns a python dict params here  
print params[’bmaj’].value, params[’bmin’].value, params[’bpa’]  
im.restore(model=’bla’ , complist=’’, image=’bla.restored’ , residual=’bla2.residual’ )  
 
 
Or if one wants to generate a psf from the uv coverage and use that subsequently as in the  following example:  
 
 
- im.fitpsf(psf=’’)  
- im.restore(model=’bla’ , complist=’’, image=’bla.restored’ , residual=’bla2.residual’ )  
 
 

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