Specifying INVERT's cell size

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Moderator: Mark.Wieringa

Specifying INVERT's cell size

Postby and460 » Fri Aug 16, 2013 11:00 am

Hi guys,

I notice that INVERT has an option that allows the cell size to be specified as a function of the image resolution - i.e. appending 'res' to the cell size parameter. The miriad task notes say that this will "specify the the cellsize in terms of the number of pixels per resolution element (e.g., cell=5,5,res)."

My question is this: Does this procedure take thee visibility weighting into account when calculating the resolution of the image and the cell size required to put a certain number of pixels across the beam? For example, if I specify a fwhm in INVERT to attempt to image to a certain resolution, will INVERT then try to put a specified no. of pixels across the beam at the 'smoothed' image resolution, or is it limited to calculating the no. of pixels required across, say, a uniformly or naturally weighted image?

Cheers,

Craig.
and460
 
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Re: Specifying INVERT's cell size

Postby Mark.Wieringa » Fri Aug 16, 2013 11:52 am

Hi Craig,

it takes tapering (fwhm) and the maximum uv distance into account, but not the weighting scheme (natural/uniform/robust), so it will tend to underestimate the number of pixels per beam for natural and robust weighting (unless fwhm is larger than the natural weight beam).

Cheers,

Mark
Mark.Wieringa
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Re: Specifying INVERT's cell size

Postby and460 » Tue Aug 20, 2013 1:29 pm

Thanks Mark!
and460
 
Posts: 79
Joined: Thu Sep 01, 2011 12:23 pm


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