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mirflag stokes option

PostPosted: Tue May 17, 2011 5:16 pm
by ilanafeain
I have CABB 16cm data which I want to flag (obviously) before calibrating. But the default in mirflag appears to be to flag in I and apply to all other stokes params. But I isn't overly meaningful before I have calibrated XX and YY. I suggest that the default should be to flag in XX and YY and then apply to XX,YY, XY,YX

But my question is this: when I ask to flag in V and then apply to all stokes params, using Stokes='V,I,Q,U,V' the task fails with the message:

##### ERROR
Invalid polarization specified: i

Any suggestions?

Many thanks for getting a version of pieflag running - I have found it to be super useful in the past!

Re: mirflag stokes option

PostPosted: Thu Dec 01, 2011 11:49 am
by len067
Hi Ilana,

Sorry to be replying so late, for some reason I was not getting informed of new postings and I only just found your posting as I was updating my contact details on the forum.

What you need to do is either stokes=v or stokes=v,xx,xy,yx,yy since you can only apply flagging to observed parameters i.e. stokes I, Q, U, and V are formed from the observed parameters. For the stokes=v case, the analysis will be done using stokes V and then all observed polarisation parameters will be flagged. The stokes=v,xx,xy,yx,yy will do exactly the same but gives you the option to select only certain target polarisation parameters e.g. xx and yy only ... though I'm not really sure under what conditions this would be useful.