[daip] DFTPL and UVPLT (fwd)

[Eric Greisen]

Farhad Zadeh writes:

 > 1) DFTPL does not seem to work with the choice of uvrange. We tried
 > any possible and impossible range but the plot looks the same.

    I don't know - I will look.

 > 
 > 2) This may be a dumb question but UVPLT using stokes "HALF" and "I" give 
 > different results. Arent' they 
 > the same?

      No.  I = (RR+LL)/2 where HALF plots RR and LL separately (and in
UVPLT I think it only plots RR if you say HALF.

 > 
 > UVFIND is in Jy (I believe) but UVPLT is not. I think I set
 > a parameter that converts to stokes I but I am still not able to
 > get the bad data that shows up in I but not in RR, LL or half.
 > Isn't RR+LL the same as I?

UVPLT is in Jy when you ask for an axis that is in Jy (amplitude,
real, imaginary).  In both tasks, of course, it depends on whether
there is calibration to make the observed vis into calibrated Jy.
(RR+LL)/2 in a vector sense is I but I think UVFND looks at the
individual correlators (with CORR) or does various conversions.  It is
harder to have bad data in I than to have it in RR and LL.  Bad data
often has out of phase RR and LL so I looks okay and is not.

Eric Greisen