[daip] Re: AIPS-DBCON

[Shinji Horiuchi]

Hi Eric,

Thank you for the information. So I understand that DBCON can form a file like
with RR and LL in different subarrays if I change one of the Stokes label
but there is no simple way to reproduce Stokes parameters, like V in this case,
using AIPS tasks for the file. Is it correct?

In fact the original fits files are the ones I created from 
Swinburne-LBA software
correlator output. My goal is to be able to generate proper fits 
files for AIPS analysis.
The program so far only generates single source format files, and for 
multi source
files I need to form by hand in AIPS using MULTI and DBCON several times
and it works so far. I was expecting the similar thing for multi 
polarization files
but it appears impossible, according to what you says, and it seems I 
should better
spend time to modify my program to write visibilities of RR, LL etc. 
in the same
uv-data entry.

Cheers,

Shinji.


>Shinji Horiuchi writes:
>
>  > I tried to conbine RR and LL files into one polarization file
>  > using DBCON but it said
>  >
>  >  DBCON1: STOKES RANGES DO NOT OVERLAP
>  >  DBCON1: Purports to die of UNNATURAL causes
>  >
>  > I checked this both for single and multi files.
>  > Does DBCON not support for merging different pols?
>  > I appreciate if you can instruct me proper method for this.
>
>That is correct - DBCON does not merge polarizations.  To merge these
>data sets change the LL into RR via puthead and then run DBCON,
>treating the 2nd data set as a 2nd subarray (DOARRAY = -1).
>
>Polarizations are assumed normally to be part of the visibility array
>occurring at exactly the same times, antennas, etc etc.  DBCON will
>not attempt to build up such arrays from the component parts and the
>two data sets are not guaranteed to have the exactly same samples.
>
>Eric Greisen

-- 
Dr. Shinji Horiuchi
Centre for Astrophysics and Supercomputing
Swinburne University of Technology
Mail No 39
P.O. Box 218, Hawthorn, VIC. 3122, Australia

ph:  +61 3 9214 5818
fax: +61 3 9214 8797
email: shoriuchi at swin.edu.au