Regriding beam to a pixel

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Regriding beam to a pixel

Postby saracmbr » Mon Sep 02, 2013 9:20 pm

Hi there,

I'm trying to regrid my image where each pixel will represent a beam size. Thus a point souse should appear as a pixel. I dont know how to do this with the task regrid in MIRID. I'm wondering if anyone can help me here.
My Image has cellsize=0.3 and the beam size is 5.4*3 arcsec^2 so now beam is taking up 18*10 pixels.

Cheers,
Sara
saracmbr
 
Posts: 38
Joined: Fri Jan 20, 2012 3:40 pm

Re: Regriding beam to a pixel

Postby Mark.Wieringa » Wed Sep 04, 2013 9:32 am

Hi Sara,

I'm not sure why you would want to reduce the beam to a single pixel, that would be undersampling the data - source fluxes and positions would not be reliable. The smallest you should normally go is two pixels per beam.
With regrid you can specify axes=1,2 and then use desc to specify the new output image parameters, you can leave the reference value the same (crval) and reduce the image size and cell size to what you want, e.g., reduce by factor 9 and 5 to get a 2x2 pixel beam.

You can use gethd in=image/crval1 etc to find out the values in the input image you need to fill in the desc parameter.

Cheers,

Mark
Mark.Wieringa
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