[daip] Image Header have incorrect Visibilities

[Eric Greisen]

jabulani maswanganye wrote:
> Dear All,
> 
> I loaded  my data wit 'ATLOD' and aparm(1)=-1, aparm(3)=1, aparm(7)=1, 
> the rest set to default. The visibilities are incorrect. The 
> visibilities are for the first scan and this has become a problem when I 
> run 'CVEL'. 'CVEL' only do run for the first scan.  My 'imh' and 'LISTR' 
> are as follows:

> AIPS 1: STOKES       2  -1.0000000E+00       1.00 -1.0000000E+00    0.00
>
There is very little that I can do to help you with this problem when I 
have only the information you have sent me.  The IMHEADER appears fine 
except that the Stokes are RR/LL when aparm(1)=1 has requested true 
Stokes (I, Q, U, V).  ATLOD is only marginally supported in AIPS - I 
have received no updates in years for any changes in ATNF formats. 
ATLOD issues lots of messages about what it is doing with polarization 
and other matters - but you did not send me those.  You did not tell me 
what is wrong with the header.  And CVEL is way too advanced a usage to 
determine if the data are good.  You need to start with much simpler 
tests.  CVEL has had issues in which it did only the first scan - but I 
believe they are fixed.  What version of AIPS are you using?

If you can provide me with more information as to what is wrong I may be 
able to help.  One useful thing would be to make the data available to 
me - probably the data set you read with ATLOD would be best although it 
may be fairly large.

Note that I will be away Thursday through Monday (our time) but am 
available today and tomorrow and after that break.

Eric Greisen