[daip] forwarded message from Eric Greisen

[Eric Greisen]

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From: Eric Greisen <egreisen at nrao.edu>
To: AIPS sign-on <aips at aoc.nrao.edu>
Cc: undisclosed-recipients:;
Date: Tue, 29 Feb 2000 13:14:21 -0500

AIPS sign-on writes:
 > Hello-
 > 
 > I'm trying to vplot my VLBA data, which I have fitld'ed, fxpol'ed,
 > indxr and mergcaled.  It is giving me the following error message:
 > 
 > VPLOT1: Task VPLOT  (release of 31DEC99) begins
 > VPLOT1: FNDPOL: The data contain only LL,RL,(LR), an illegal combination
 > VPLOT1: SCALVB: ERROR  1 INIT VIS FILE
 > VPLOT1: Purports to die of UNNATURAL causes
 > 
 > I'm in room 257 on comanche if its easier to talk in person.
 > 
I am unfamiliar with the requirement for FXPOL.  It appears that that
task (a) does not write in the history file and (b) does not change
the reference value for the Stokes.  I guess that it assumes that it
is -1.  But in your case, the header now says that there are only LL
and RL stokes in the data.  This is not right.  It could be that there
are RR and LL and the reference value on the Stokes axis should be -1
or that there really were 8 IFs and only LL polarization in your data
in the first place - meaning that FXPOL should not have bben run.

Chris, can you stop by and check on this?

Thanks, Eric
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