A new version (1.13) of listscan, gvfits are updated in the defaut place (astro0:/astro/bin/Linux). This version computes the (u,v,w) co-ordinates at the center of the integration. It will work correctly for current as well as archival data. For LTA files made using older versions of DAS (i.e. prior to the polar mode, 2.00) the correction assumes that LTA1 was set to the default of 16 ( 2 sec). Variable LTA2s are handled. For LTA files produced using DAS versions greater than 2.00, the correction is correct for all combinations of LTA1 and LTA2.
In detail, the logfile now has a parameter called TIMESTAMP_OFF. Depending on its value, the program either
(a) leaves the timestamp unchanged from that in the ltafile
(b) moves the timestamp to the center of the integration or
(c) moves the timestamp by an amount specified by the user.
In addition in the current version of gvfits, some additional information (e.g. the project code, the name of the original LTA file) are added to the history information.
Dave Green also has a AIPS routine to recompute the UVW co-ordinates. This may be useful for people who have already flagged and calibrated their data. Help file and program text can be downloaded from: http://www.mrao.cam.ac.uk/ dag/UVFXT
This version of listscan and gvfits also takes care of frequency increment issues due to change of keyword from 'SIDEBAND' to 'SIDE BAND' in AIPS since 31DEC2005 version. In this version of AIPS, the keyword 'SIDE BAND' in the FQ (frequency) table was changed to 'SIDEBAND' for consistency with other AIPS tables.
The FITS files created by this latest version of listscan and gvfits are also compatible with the versions of AIPS earlier than 31DEC05. In case you have a FITS file generated by version 1.11 (or prior) of listscan&gvfits and want to use 31DEC05 version of AIPS ,you need to edit the FQ table in AIPS to fix the keyword 'SIDE BAND' to 'SIDEBAND'.