[evlatests] Dynamic range of images from Widar.

[Steven T. Myers]

On Mon, 9 Nov 2009, Vivek Dhawan wrote:

> 2. Whence the non-closing errors?
>
> If BL errors originate in polarization leakage, then the correction
> for a baseline should correlate with the magnitude of polarization
> leakage (D-term) on that baseline.
>
> Plots:
> 1. BL correction (re & im) vs. pol leakage - only weak correlation.

I fear we should not read too much into this.  As George has pointed out
that the leakages in the 1+D_iRD_jR* term (for RR) are not the same leakages as 
come out of the PCAL/polcal cross-hand leakages which come from solving for
(D_iR + D_jL*) like terms, which have a degeneracy for example where an offset 
d_RL can be added to each D_iR and its conjugate subtracted from D_jL without 
changing the solution.  In this model, the RR_ij is corrupted by 
[1 + (D_iR+D_RL)(D_jR*+D_RL*)]
    = [1 + D_iRD_jR* + D_iRD_RL* + D_jR*D_RL + D_RL^2]
of which the non-closing part is the ratio of this to its antenna-based average.
George can elaborate if I'm too far off-base.

   -s