[CLEAN\]UV_FIELDS RaVar DecVar [Unit] [/CENTER Ra Dec] /FILE File
Replace fields ID by Fields offsets in a Mosaic UV Table. This can
only work for a Mosaic UV table with Fields offsets, or Phase center
offsets. It cannot operate on a UV table with Pointing center offsets.
For files imported from UVFITS, the Fields offsets are found in the AIPS
SU Table which is not decoded by the FITS command, but only through the
DEFINE FITS command.
The UV_FIELDS command allows to convert the Field IDs column of the UV
table into Phase Offsets columns, and insert the proper coordinates.
Unit specifies the unit of the RaVar and DecVar variables. It can be DE-
GREE, MINUTE, SECONDS, RADIAN or ABSOLUTE.
If ABSOLUTE, RaVar and DecVar are assumed to character variable arrays
handling the Right Ascension and Declinations of the fields expressed in
sexagesimal format.
The typical use is after a DEFINE FITS A File.uvfits command, which
gives the (Ra,Dec) positions of the field centers in Degrees in
A%aips_su%col%raepo and A%aips_su%col%decepo variables:
fits File.uvfits to File.uvt
define fits A File.uvfits
define double ra dec
define char*16 cra cdec
let cra ra /sexag d H
let cdec dec /sexag d d
compute ra mean a%aips_su%col%raepo
compute dec mean a%aips_su%col%decepo
!
uv_fields a%aips_su%col%raepo a%aips_su%col%decepo DEGREE -
/FILE File.uvt /CENTER 'CRa' 'CDec'
!
This command is used in the fits_to_uvt.ima script. Note that a proper
use also requires to set the reference coordinate to Ra and Dec consis-
tently in the UV Table.
Subsections
Gildas manager
2023-06-01