[daip] CLCOR bug with GMRT data?

[Eric Greisen]

Andy Biggs wrote:
> Hi there. I've used CLCOR to shift a very bright source in a wide-field map to the phase centre. After running CLCOR, the coordinates in the header match those of the source I've tried to shift so it would appear as if the corrections I entered are correct. However, when I apply the CL table in VPLOT and POSSM, the data look visibly worse. I then inverted the CL table with CLINV and everything then looks as I would expect i.e. the large delay in POSSM and the phase wrapping in VPLOT have both disappeared.
> 
> If the above does indicate some kind of error (other than on my part) is there anything I should send you to help diagnose the problem? This was in 31DEC11 - a midnight job was run last week I think.
> 
> The XYZHAND parameter in the AN table is "right". The rest of the AN table keywords are:
> 
> GROTHN5     .SPLAT .   1  Disk= 1    AN Table version   1
> Title: AIPS UV DATA FILE ANTENNA TABLE
> Created by      SPLAT on 18-SEP-2011 01:39:08
> Last written by SPLAT on 18-SEP-2011 01:39:08
> Ncol  14  Nrow      30    Sort cols:
>     Table has    21 keyword-value pairs:
>    ARRAYX   =  1.6570046290000D+06
>    ARRAYY   =  5.7978943801000D+06
>    ARRAYZ   =  2.0733031705000D+06
>    GSTIA0   =  3.0076365628670D+03
>    DEGPDY   =  3.6098564497437D+02
>    FREQ     =  6.1025000000000D+08
>    RDATE    =  20080128
>    POLARX   =  0.0000000000000D+00
>    POLARY   =  0.0000000000000D+00
>    UT1UTC   =  0.0000000000000D+00
>    DATUTC   =  0.0000000000000D+00
>    TIMSYS   =  IAT
>    ARRNAM   =  GMRT
>    XYZHAND  =  RIGHT
>    FRAME    =  ?????
>    NUMORB   =            0
>    NOPCAL   =            2
>    NO_IF    =            2
>    FREQID   =           -1
>    IATUTC   =  3.3000000000000D+01
>    POLTYPE  =  APPROX
> 
> Thanks.
>

GMRT persists in using an opposite phase convention and we keep 
forgetting that.  I have added IF (GMRT) statements several places in 
the CLCOR where delays are computed.

Thanks

Eric Greisen