[daip] Calibration question

[Eric Greisen]

Jessica L. Rosenberg writes:

 > I suspect that this problem is arising because I worked on these data some time
 > ago now and am trying to come back to them. I used VLARESET before restarting
 > the calibration, but something is still not quite right.
 > 
 > I got to the point of running VLACLCAL and then LISTR with DOCALIB TRUE and had
 > a look at the results, but the data were not calibrated - the amplitudes were
 > still off from what GETJY reported and the phases were not small. I got rid of
 > my CL table and ran CLCAL (don't know what the difference between these two is)
 > but got the same results. This time I took more close note of the info being
 > reported which was as follows:
 > 
 > leavit> CLCAL1: Task CLCAL  (release of 31DEC02) begins
 > leavit> CLCAL1: You are using a non-standard program
 > leavit> CLCAL1: Using interpolation mode 2PT
 > leavit> CLCAL1: Processing SN table    0
 > leavit> CLCAL1: WARNING: SN table    1 has already been applied
 > leavit> CLCAL1: SN2CL: Applying SN tables to CL table   1, writing CL table  2
 > leavit> CLCAL1: SN2CL: Appending new solutions to CL table   2
 > leavit> CLCAL1: SN2CL: WARNING: NO CL RECORDS WRITTEN
 > leavit> CLCAL1: Appears to have ended successfully
 > leavit> CLCAL1: leavitt      31DEC02 TST: Cpu=       0.5  Real=       7
 > leavit> CLCAL1: Task CLCAL  (release of 31DEC02) begins
 > leavit> CLCAL1: You are using a non-standard program
 > leavit> CLCAL1: Using interpolation mode 2PT
 > leavit> CLCAL1: Processing SN table    0
 > leavit> CLCAL1: WARNING: SN table    1 has already been applied
 > leavit> CLCAL1: SN2CL: Applying SN tables to CL table   1, writing CL table  2
 > leavit> CLCAL1: SN2CL: Appending new solutions to CL table   2
 > leavit> CLCAL1: leavitt      31DEC02 TST: Cpu=       0.5  Real=       7
 > leavit> CLCAL1: Task CLCAL  (release of 31DEC02) begins
 > leavit> CLCAL1: You are using a non-standard program
 > leavit> CLCAL1: Using interpolation mode 2PT
 > leavit> CLCAL1: Processing SN table    0
 > leavit> CLCAL1: WARNING: SN table    1 has already beenvit> LISTR1: ZTXOP2: LIST
 > R_MATX3.TXT
 > leavit> LISTR1: CL TABLE IS EMPTY: SETTING DOCAL FALSE
 > leavit> LISTR1: Appears to have ended successfully

     I do not understand this - VLACLCAL runs CLCAL only once, not 3
times.  I need to see the IMHEADER, and the inputs to CLCAL.  I notice
that the inputs file and perhaps the help file for vlaclcal does not
say the correct information for the current clcal.  The warning is to
try to prevent an SN table from being applied more than once in
succession to the CL (e.g. CL 1 + SN 1 -> CL 2 then CL2 + SN 1 -> CL3,
etc so that the corrections are made twice.  You will get this as a
warning only to alert you in case you are doing wrong things but it
will not stop you from e.g. CL1 + SN 1 more than once.

I just noticed that you are using a rather old version of aips but one
that we can still try.  CLCAL has been worked upon and improved but
the fixed/improved parts are not likely to be the source of your
trouble.  When you generate the SN table do you apply CL table 1 to
the data in CALIB?  What are the contents of the SN and CL table -
sources, times, antennas, etc Were there a lot of failed solutions in
CALIB?

You see I have many more questions about yopur data than answers with
just the above messages.

Eric Greisen

 > 
 > So no CL records are being written, but I am not sure what the WARNING: SN table
 > 1 has already been applied is all about, where it was applied, or how I go about
 > dealing with this situation. As I said I think it may be because I played with
 > these data before, but if so how do I get things restarted so that I don't run
 > into this problem?
 > 
 > Thanks!
 > Jessica
 > 
 > -----------------------------------------------------
 > Jessica Rosenberg           Campus Box 389, CASA
 > phone: 303-735-4190         University of Colorado
 > fax: 303-492-7178           Boulder, CO  80309
 > 
 > e-mail: jrosenbe at casa.colorado.edu
 > -----------------------------------------------------
 > 
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