[daip] Help please

[Leonia Kogan]

Johan,

If CALIB (inside of VLACALIB) found 208 good solution and failued 
to find solution for 7 instances, it is not bad.

>Assuming that the 208 good solutions is a good sign I decided to go on
>and calculate the flux densities of the secondary (phase) calibrators with
>GETJY. I tried that on one secondary calibrator for a start. However,
>the calculated flux density came out as zero. 

I can think about the two possible errors:

1. Using SETJY you might use ZEROSP=0 forcing SETJY calculate the flux 
   of the "primary" calibrator, which is actually not primary in you case. 
   SETJY can calculate flux only for the primary calibrators: 3C286
   or 3C48. You can check the flux of your "primary" calibrator printing 
   SU table by PRTAB.

2. Using VLACALIB you might forget to include your secondary calibrator 
   in the list of CALSOUR. 

If it does not help, send me the input parameters of SETJY, VLACALIB and 
GETJY that you used.

Leonia

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>From johan at fskdjvdw.puk.ac.za Tue Mar 28 02:57 MST 2000
Date: Tue, 28 Mar 2000 11:56:48 +0200 (SAST)
From: Johan van der Walt <johan at fskdjvdw.puk.ac.za>
To: lkogan at cv3.cv.nrao.edu
Subject: Help please
MIME-Version: 1.0
X-Lines: 37
Status: RO

I am a new user of the VLA and therefore also a new user of AIPS.
We had an observing run on 13 Nov last year and I went to Socorro a
couple of weeks ago to get into the basic things about AIPS.

I am now in the process of the data reduction and ran into a problem
which I don't know how to solve. I followed the AIPS Cookbook Chapter 4
for the calibration of the data. I had my data on a DAT tape and
succesfully loaded on my pc. There was a computer problem during the
observations which meant that our primary calibrator was not observed.
We therefore have to use one of the secondary calibrators as a primary
calibrator. Using TVFLG and UVPLT I inspected the data and removed all
the really suspicious data. I then used SETJY to set the flux density
of the calibrator and ran VLACALIB. This seemed to ended successfully
although it is not quite clear to me how to interpret the output of
VLACALIB. At the end of the message it says that it found 208 good
solutions and for 7 instances it reported excess closure errors. 

Questions:  (1): What does it mean if eg. it is reported that antenna 7
had 1 excess closure error?
            (2): What does the following mean: Average closure error
1.737%  0.93d? Is that something serious? Or something like
07-20 32.2% 23d?

Assuming that the 208 good solutions is a good sign I decided to go on
and calculate the flux densities of the secondary (phase) calibrators with
GETJY. I tried that on one secondary calibrator for a start. However,
the calculated flux density came out as zero. This happened with all
the other secondary calibrators as well. Surely this cannot be correct?

Is there anything obvious that I didn't do?

Regards

Johan van der Walt





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