[daip] UVFIX (B1950 to J2000 coordinates)

[Eric Greisen]

Teddy Cheung wrote:
> Hello,
> 
> I'm working on some archival VLA data (from 1996) obtained with B1950
> coordinates and I thought I used UVFIX correctly (I ran it on the
> Multi-source file right after FILLM). However, I'm googling and came
> across this passage stating UVFIX does not handle multi-source files:
> 
> http://www.atnf.csiro.au/computing/at_bugs.html#Bug_16
> 
> Is this true? I looked at the calibrator positions in the LISTR output
> of the UVFIXed file and found no large discrepancies when comparing to
> positions in the VLA calibrator manual (most cal man positions were
> obtained in 2001 and I assumed any small differences I see in the 1996
> data were simply due to less well-known positions at the earlier
> time).
> 
> If I did screw up, is there a way to un-UVFIX and then correctly UVFIX
> my files? I've already self-caled the SPLIT files.

UVFIX should, these days, handle multi-source files just fine.  The bug 
listing above was for the ATCA on-line system and has nothing to do with 
AIPS directly.  I believe UVFIX did have some trouble with multi-source 
files quite a while ago - that has been fixed entirely.  You can grep 
$AIPSPUBL/CHANG* for UVFIX if you want to see the history in detail.

Eric Greisen