[daip] Antenna Issue

[Eric Greisen]

Doug Gobeille wrote:
> Dearest DAIP,
> 
> I had an issue recently when downloading a project from the archives, 
> specifically project AS0218 (5/31-6/1/85). I've downloaded the project 
> three times now and each time I load it into AIPS it doesn't seem to 
> have any antenna data. Is this an archival issue or perhaps something 
> with AIPS?
> 
> Cheers,

You and FILLM are not making errors I think.  In the earliest days of 
the VLA, antenna data were recorded in the Monitor data base and only 
available several days after the observing run.  Getting the antenna 
info back into the archive in the right place and format was a major 
achievement when the old old archive was recopied and the format 
translated.  I am not surprised that AN info is occasionally missing.

You have 2 choices if you want to process these data:

1. Live with no AN file.  This means that you remain in B1950 
coordinates and do NOT run UVFIX.  The final images may be converted 
with the EPOSW verb (giving a rotated image) and if you want regridded 
with HGEOM or OHGEO.

2. Download other data sets at times close to this one and see if they 
have a valid AN file.  If so use TACOP to copy the table to your data.
Then you can use UVFIX (which I would be inclined to do on old data).
BUT I would double check that the uvw's out of UVFIX are not grossly 
different from those beforehand (they will be rotated some due to the 
equinox switch).  A gross difference would suggest that the AN file is 
not correct (i.e. antennas moved).

Eric Greisen