AIPS NRAO AIPS HELP file for CORFQ in 31DEC21



As of Wed Oct 27 21:54:39 2021


CORFQ: Task to correct uvw for an incorrect obs. frequency.

INPUTS

INNAME                             UV data (name).
INCLASS                            UV data (class).
INSEQ             0.0    9999.0    UV data (seq. #).  0 => high
INDISK            0.0       9.0    Disk unit #.  0 => any
FACTOR                             Correction factor, if 0.0
                                   then the 2cm (1981) problem
                                   is corrected.(see HELP CORFQ)

HELP SECTION

CORFQ
Type:  Task
Use:   This task corrects for an incorrect observing frequency
       used in a data base.  It corrects uvw by abs(FACTOR).  If
       FACTOR >= 0, it also corrects the observing frequency in the
       header and in the antenna file.
Adverbs:
  INNAME.....UV file name (name).     Standard defaults.
  INCLASS....UV file name (class).    Standard defaults.
  INSEQ......UV file name (seq. #).   0 => highest.
  INDISK.....Disk unit #.             0 => any.
  FACTOR.....Correction factor for frequency and uvw.
             0.0 => FACTOR = (FREQ - BANDWID) / FREQ
             <0 => correct only u,v,w by abs(FACTOR)
             >0 -> correct header and antennna file header also

EXPLAIN SECTION

CORFQ:  Task to correct uvw for an incorrect obs. frequency.
DOCUMENTOR: C.P. O'Dea   NRAO/VLA
RELATED PROGRAMS: IMHEADER, UVCOP

                         PURPOSE

     CORFQ corrects the frequency in the header and the uvw in a
uv data base (units are in wavelengths) by multiplying these
quantities by FACTOR.  The corrections are applied in situ, ie.,
a new data base is not created.

                         COMMENTS

FACTOR:
     FACTOR should be chosen such that:

        FACTOR = (correct frequency)/(current frequency).

The default of 0 gives:

               FACTOR = (freq - bandwidth)/freq.

This corrects a past problem at 2cm where the frequency used
was too large by the bandwidth.

AIPS